Ritonavir Interactions

Other Agents Alpha 1-Adrenoreceptor Antagonist: alfuzosin ↑ alfuzosin Contraindicated due to potential hypotension [see Contraindications (4) ].

Source: FDA drug label - ritonavir

( 7.1 ) Use with CYP3A Inhibitors (except ritonavir): Increase the risk of adverse reactions of alprazolam. Strong Inhibitors of CYP3A (except ritonavir) Clinical implication Concomitant use of alprazolam with strong CYP3A inhibitors has a profound effect on the clearance of alprazolam, resulting in increased concentrations of alprazolam and increased risk of adverse reactions [see Clinical Pharmacology (12.3) ]. Prevention or management Concomitant use of alprazolam with a strong CYP3A4 inhibitor (except ritonavir) is contraindicated [see Contraindications (4) , Warnings and Precautions (5.5) ].

Source: FDA drug label - alprazolam

Anticancer Agents: abemaciclib, apalutamide, dasatinib, encorafenib, ibrutinib, ivosidenib, neratinib, nilotinib, venetoclax, vinblastine, vincristine ↑ anticancer agents ↓ ritonavir # Apalutamide is contraindicated due to potential for loss of virologic response and possible resistance to ritonavir or to the class of protease inhibitors [see Contraindications (4) ] . # refers to interaction with apalutamide.

Source: FDA drug label - ritonavir

Lipid-modifying agents HMG-CoA Reductase Inhibitor: lovastatin simvastatin atorvastatin rosuvastatin Microsomal triglyceride transfer protein (MTTP) Inhibitor: lomitapide ↑ lovastatin ↑ simvastatin ↑ atorvastatin ↑ rosuvastatin ↑ lomitapide Contraindicated due to potential for myopathy including rhabdomyolysis [see Contraindications (4) ]. Titrate atorvastatin and rosuvastatin dose carefully and use the lowest necessary dose. If ritonavir is used with another protease inhibitor, see the complete prescribing information for the concomitant protease inhibitor for details on co- administration with atorvastatin and rosuvastatin.

Source: FDA drug label - ritonavir

Lipid-modifying agents HMG-CoA Reductase Inhibitor: lovastatin simvastatin atorvastatin rosuvastatin Microsomal triglyceride transfer protein (MTTP) Inhibitor: lomitapide ↑ lovastatin ↑ simvastatin ↑ atorvastatin ↑ rosuvastatin ↑ lomitapide Contraindicated due to potential for myopathy including rhabdomyolysis [see Contraindications (4) ].

Source: FDA drug label - ritonavir

Sedative/Hypnotics: triazolam, orally administered midazolam ↑ triazolam ↑ midazolam Contraindicated due to potential for prolonged or increased sedation or respiratory depression [see Contraindications (4) ] . Sedative/hypnotics: Parenteral midazolam ↑ midazolam Co-administration should be done in a setting which ensures close clinical monitoring and appropriate medical management in case of respiratory depression and/or prolonged sedation. Dosage reduction for midazolam should be considered, especially if more than a single dose of midazolam is administered.

Source: FDA drug label - ritonavir

( 7.2 ) 7.1 Effects of Other Drugs on Ranolazine Strong CYP3A Inhibitors Do not use ranolazine with strong CYP3A inhibitors, including ketoconazole, itraconazole, clarithromycin, nefazodone, nelfinavir, ritonavir, indinavir, and saquinavir [see Contraindications (4) , Clinical Pharmacology (12.3) ].

Source: FDA drug label - ranolazine

7 DRUG INTERACTIONS Sildenafil can potentiate the hypotensive effects of nitrates, alpha blockers, and anti-hypertensives ( 4.1 , 5.5 , 7.1 , 7.2 , 7.3 , 12.2 ) With concomitant use of alpha blockers, initiate sildenafil at 25 mg dose ( 2.3 ) CYP3A4 inhibitors (e.g., ritonavir, ketoconazole, itraconazole, erythromycin): Increase sildenafil exposure ( 2.4 , 7.4 , 12.3 ) Ritonavir: Do not exceed a maximum single dose of 25 mg in a 48 hour period ( 2.4 , 5.6 ) Erythromycin or strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, saquinavir): Consider a starting dose of 25 mg ( 2.4 , 7.4 ) 7.1 Nitrates Administration of sildenafil with nitric oxide donors such as organic nitrates or organic nitrites in any form is contraindicated. 7.4 Ritonavir and other CYP3A4 inhibitors Co-administration of ritonavir, a strong CYP3A4 inhibitor, greatly increased the systemic exposure of sildenafil (11-fold increase in AUC).

Source: FDA drug label - sildenafil citrate

Sedative/Hypnotics: triazolam, orally administered midazolam ↑ triazolam ↑ midazolam Contraindicated due to potential for prolonged or increased sedation or respiratory depression [see Contraindications (4) ] .

Source: FDA drug label - ritonavir

In vivo studies Do not use vardenafil orally disintegrating tablet with moderate and strong CYP3A4 inhibitors such as erythromycin, grapefruit juice, clarithromycin, ketoconazole, itraconazole, indinavir, saquinavir, atazanavir, ritonavir as the systemic concentration of vardenafil is increased in their presence [see Warnings and Precautions (5) and Dosage and Administration ( 2.4 )] . [See Dosage and Administration (2.4) and Warnings and Precautions ( 5 ).] Ritonavir (600 mg b.i.d.) co-administered with vardenafil 5 mg resulted in a 49-fold increase in vardenafil AUC and a 13-fold increase in vardenafil C max . The interaction is a consequence of blocking hepatic metabolism of vardenafil by ritonavir, a HIV protease inhibitor and a highly strong CYP3A4 inhibitor, which also inhibits CYP2C9.

Source: FDA drug label - vardenafil

High-dose Ritonavir (400 mg every 12 hours) (CYP450 Induction) Significantly Reduced Contraindicated Low-dose Ritonavir (100 mg every 12 hours) (CYP450 Induction) Reduced Concomitant administration of voriconazole and low-dose ritonavir (100 mg every 12 hours) should be avoided, unless an assessment of the benefit/risk to the patient justifies the use of voriconazole. High-dose Ritonavir (400 mg every 12 hours) (CYP3A4 Inhibition) No Significant Effect of Voriconazole on Ritonavir C max or AUC τ Contraindicated because of significant reduction of voriconazole C max and AUC τ. Low-dose Ritonavir (100 mg every 12 hours) Slight Decrease in Ritonavir C max and AUC τ Concomitant administration of voriconazole and low-dose ritonavir (100 mg every 12 hours) should be avoided (due to the reduction in voriconazole C max and AUC τ ) unless an assessment of the benefit/risk to the patient justifies the use of voriconazole.

Source: FDA drug label - ritonavir

7 DRUG INTERACTIONS When co-administering ritonavir with other protease inhibitors (atazanavir, darunavir, fosamprenavir, saquinavir, and tipranavir), see the full prescribing information for that protease inhibitor including important information for drug interactions. HIV-1 Protease Inhibitor: saquinavir ↑ saquinavir See the complete prescribing information for saquinavir for details on co-administration of saquinavir and ritonavir. Saquinavir/ritonavir in combination with rifampin is not recommended due to the risk of severe hepatotoxicity (presenting as increased hepatic transaminases) if the three drugs are given together.

Source: FDA drug label - ritonavir

Anticancer Agents: abemaciclib, apalutamide, dasatinib, encorafenib, ibrutinib, ivosidenib, neratinib, nilotinib, venetoclax, vinblastine, vincristine ↑ anticancer agents ↓ ritonavir refers to interaction with apalutamide. Avoid co-administration of encorafenib or ivosidenib with ritonavir due to potential risk of serious adverse events such as QT interval prolongation. If co-administration of encorafenib with ritonavir cannot be avoided, modify dose as recommended in encorafenib USPI.

Source: FDA drug label - ritonavir

Intervention Avoid concomitant use of FOCINVEZ Examples Moderate inhibitor: diltiazem Strong inhibitors: ketoconazole, itraconazole, nefazodone, troleandomycin, clarithromycin, ritonavir, nelfinavir Strong CYP3A4 Inducers Clinical Impact Substantially decreased exposure of aprepitant in patients chronically taking a strong CYP3A4 inducer may decrease the efficacy of FOCINVEZ [see Clinical Pharmacology (12.3)] .

Source: FDA drug label - fosaprepitant dimeglumine

Anticancer Agents: abemaciclib, apalutamide, dasatinib, encorafenib, ibrutinib, ivosidenib, neratinib, nilotinib, venetoclax, vinblastine, vincristine ↑ anticancer agents ↓ ritonavir refers to interaction with apalutamide. Avoid use of neratinib, venetoclax or ibrutinib with ritonavir.

Source: FDA drug label - ritonavir

Anticancer Agents: abemaciclib, apalutamide, dasatinib, encorafenib, ibrutinib, ivosidenib, neratinib, nilotinib, venetoclax, vinblastine, vincristine ↑ anticancer agents ↓ ritonavir refers to interaction with apalutamide. Avoid co-administration of encorafenib or ivosidenib with ritonavir due to potential risk of serious adverse events such as QT interval prolongation. If co-administration of ivosidenib with ritonavir cannot be avoided, reduce ivosidenib dose to 250 mg once daily.

Source: FDA drug label - ritonavir

Anticancer Agents: abemaciclib, apalutamide, dasatinib, encorafenib, ibrutinib, ivosidenib, neratinib, nilotinib, venetoclax, vinblastine, vincristine ↑ anticancer agents ↓ ritonavir refers to interaction with apalutamide. Avoid use of neratinib, venetoclax or ibrutinib with ritonavir.

Source: FDA drug label - ritonavir

Drug Interactions Pharmacodynamic Interactions Healthy subjects who received rifampin 600 mg once daily concomitantly with saquinavir 1000 mg/ritonavir 100 mg twice daily (ritonavir-boosted saquinavir) developed severe hepatocellular toxicity.

Source: FDA drug label - rifampin

7.2 Drugs that Inhibit Cytochrome P450 3A Enzymes and Drug Transport Systems Interaction with Combined P-gp and Strong CYP3A Inhibitors Avoid concomitant administration of XARELTO with known combined P-gp and strong CYP3A inhibitors (e.g., ketoconazole and ritonavir) [see Warnings and Precautions (5.6) and Clinical Pharmacology (12.3) ] .

Source: FDA drug label - rivaroxaban

Increase tacrolimus dose and monitor tacrolimus whole blood trough concentrations [see Dosage and Administration ( 2.2 , 2.6 ) and Clinical Pharmacology (12.3 ) ] Strong CYP3A Inhibitors : Protease inhibitors (e.g, nelfinavir, telaprevir, boceprevir, ritonavir), azole antifungals (e.g., voriconazole, posaconazole, itraconazole, ketoconazole), antibiotics (e.g., clarithromycin, troleandomycin, chloramphenicol), nefazodone,letermovir, Schisandra sphenanthera extracts May increase tacrolimus whole blood trough concentrations and increase the risk of serious adverse reactions (e.g., neurotoxicity, QT prolongation).A rapid, sharp rise in tacrolimus levels may occur early, despite an immediate reduction of tacrolimus dose [see Warnings and Precautions ( 5.6 , 5.11 , 5.12 )] Reduce tacrolimus dose (for voriconazole and posaconazole, give one-third of the original dose) and adjust dose based on tacrolimus whole blood trough concentrations [see Dosage and Administration ( 2.2 , 2.6 ) and Clinical Phamacology ( 12.3 )].

Source: FDA drug label - tacrolimus

Strong CYP3A Inhibitors : Protease inhibitors (e.g., nelfinavir, telaprevir, boceprevir, ritonavir), azole antifungals (e.g., voriconazole, posaconazole, itraconazole, ketoconazole), antibiotics (e.g., clarithromycin, troleandomycin, chloramphenicol), nefazodone, letermovir, Schisandra sphenanthera extracts May increase tacrolimus whole blood trough concentrations and increase the risk of serious adverse reactions (e.g., neurotoxicity, QT prolongation).

Source: FDA drug label - tacrolimus extended-release capsules

Avoid use of strong inhibitors of CYP3A (e.g., ketoconazole, itraconazole, voriconazole, clarithromycin, nefazodone, ritonavir, saquinavir, nelfinavir, indinavir, atazanavir and telithromycin) [see Clinical Pharmacology ( 12.3 )] .

Source: FDA drug label - ticagrelor

• Strong cytochrome P450 3A4 inhibitors (e.g., ritonavir): Use with caution. Caution should be exercised when considering the coadministration of budesonide and formoterol fumarate dihydrate with long-term ketoconazole and other known strong CYP3A4 inhibitors (e.g., ritonavir, atazanavir, clarithromycin, indinavir, itraconazole, nefazodone, nelfinavir, saquinavir, telithromycin) [see Warnings and Precautions (5.9) ] .

Source: FDA drug label - budesonide and formoterol fumarate dihydrate

Antiarrhythmics: disopyramide, lidocaine, mexiletine ↑ antiarrhythmics Caution is warranted and therapeutic concentration monitoring is recommended for antiarrhythmics when co-administered with ritonavir, if available.

Source: FDA drug label - ritonavir

7 DRUG INTERACTIONS Use with caution in patients taking potent, chronic cytochrome P450 (CYP)3A4 enzyme inhibitors (e.g., ritonavir). Because of the potential for drug-drug interactions, use caution when prescribing dutasteride to patients taking potent, chronic CYP3A4 enzyme inhibitors (e.g., ritonavir) [see Clinical Pharmacology (12.3)] .

Source: FDA drug label - dutasteride

Because of the potential for drug-drug interactions, use caution when prescribing a dutasteride-containing product, including dutasteride and tamsulosin hydrochloride capsules, to patients taking potent, chronic CYP3A4 enzyme inhibitors (e.g., ritonavir) [see Clinical Pharmacology ( 12.3 ) ] .

Source: FDA drug label - dutasteride and tamsulosin hydrochloride capsules

When coadministered with emtricitabine and tenofovir disoproxil fumarate, use atazanavir given with ritonavir. HIV-1 Protease Inhibitors: atazanavir c lopinavir/ritonavir c atazanavir/ritonavir c darunavir/ritonavir c ↓ atazanavir ↑ tenofovir When coadministered with emtricitabine and tenofovir disoproxil fumarate, atazanavir 300 mg should be given with ritonavir 100 mg. Monitor patients receiving emtricitabine and tenofovir disoproxil fumarate concomitantly with lopinavir/ritonavir, ritonavir-boosted atazanavir, or ritonavir-boosted darunavir for TDF-associated adverse reactions.

Source: FDA drug label - emtricitabine and tenofovir disoproxil fumarate

Kinase Inhibitors: fostamatinib (also see anticancer agents above ) ↑ fostamatinib metabolite R406 Monitor for toxicities of R406 exposure resulting in dose-related adverse events such as hepatotoxicity and neutropenia. Fostamatinib dose reduction may be required.

Source: FDA drug label - ritonavir

Drug Interactions Effects of Other Drugs on Loperamide Concomitant use of loperamide hydrochloride capsules with inhibitors of CYP3A4 (e.g., itraconazole) or CYP2C8 (e.g., gemfibrozil) or inhibitors of P-glycoprotein (e.g., quinidine, ritonavir) can increase exposure to loperamide. P-glycoprotein Inhibitors Concomitant administration of a 16 mg single dose of loperamide hydrochloride with a 600 mg single dose of quinidine or ritonavir, both of which are P-glycoprotein inhibitors, resulted in a 2- to 3-fold increase in loperamide plasma concentrations. Due to the potential for enhanced CNS adverse reactions when loperamide is coadministered with quinidine and with ritonavir, caution should be exercised when loperamide hydrochloride capsules are administered at the recommended dosages (2 mg, up to 16 mg maximum daily dose) with P-glycoprotein inhibitors.

Source: FDA drug label - loperamide hydrochloride

Examples: Ketoconazole, clarithromycin, ritonavir, voriconazole, mibefradil Moderate CYP3A4 Inhibitors Clinical Impact: Concomitant use of lurasidone hydrochloride with moderate CYP3A4 inhibitors increased the exposure of lurasidone compared to the use of lurasidone hydrochloride alone [see Clinical Pharmacology ( 12.3 )].

Source: FDA drug label - lurasidone hydrochloride

β-Blockers: metoprolol, timolol ↑ beta-blockers Caution is warranted and clinical monitoring of patients is recommended.

Source: FDA drug label - ritonavir

Strong cytochrome P450 3A4 inhibitors (e.g., ritonavir): Use with caution. Caution should be exercised when considering the coadministration of ASMANEX HFA with long-term ketoconazole and other known strong CYP3A4 inhibitors (e.g., ritonavir, cobicistat-containing products, atazanavir, clarithromycin, indinavir, itraconazole, nefazodone, nelfinavir, saquinavir, telithromycin) [see Warnings and Precautions (5.6) and Clinical Pharmacology (12.3) ] .

Source: FDA drug label - mometasone furoate

Caution should be exercised when paclitaxel is concomitantly administered with known substrates (e.g., midazolam, buspirone, felodipine, lovastatin, eletriptan, sildenafil, simvastatin, and triazolam), inhibitors (e.g., atazanavir, clarithromycin, indinavir, itraconazole, ketoconazole, nefazodone, nelfinavir, ritonavir, saquinavir, and telithromycin), and inducers (e.g., rifampin and carbamazepine) of CYP3A4. Potential interactions between paclitaxel, a substrate of CYP3A4, and protease inhibitors (ritonavir, saquinavir, indinavir, and nelfinavir), which are substrates and/or inhibitors of CYP3A4, have not been evaluated in clinical trials.

Source: FDA drug label - paclitaxel

Concomitant administration of a Moderate CYP 3A inducer, such as efavirenz, should be avoided unless the benefit outweighs the risks [see Warnings and Precautions (5.6) and Clinical Pharmacology (12.3) .] 7.2 CYP450 Inhibitors Concomitant administration of drugs that decrease the activity of drug metabolizing liver enzymes (CYP450 inhibitors), for example, cimetidine, ketoconazole, itraconazole, erythromycin, and ritonavir may increase plasma concentrations of praziquantel.

Source: FDA drug label - praziquantel

When coadministered with tenofovir disoproxil fumarate, use atazanavir given with ritonavir. HIV-1 Protease Inhibitors : atazanavir lopinavir/ritonavir atazanavir/ritonavir darunavir/ritonavir ↓ atazanavir ↑ tenofovir When coadministered with tenofovir disoproxil fumarate tablets, atazanavir 300 mg should be given with ritonavir 100 mg. Monitor patients receiving tenofovir disoproxil fumarate tablets concomitantly with lopinavir/ritonavir, ritonavir-boosted atazanavir, or ritonavir-boosted darunavir for tenofovir DF-associated adverse reactions.

Source: FDA drug label - tenofovir disoproxil fumarate

β-Blockers: metoprolol, timolol ↑ beta-blockers Caution is warranted and clinical monitoring of patients is recommended.

Source: FDA drug label - ritonavir

Anticancer Agents: abemaciclib, apalutamide, dasatinib, encorafenib, ibrutinib, ivosidenib, neratinib, nilotinib, venetoclax, vinblastine, vincristine ↑ anticancer agents ↓ ritonavir refers to interaction with apalutamide.

Source: FDA drug label - ritonavir

Intervention: Concomitant use of tipranavir plus ritonavir or glecaprevir plus pibrentasvir with atorvastatin is not recommended. In patients taking lopinavir plus ritonavir, or simeprevir, consider the risk/benefit of concomitant use with atorvastatin. In patients taking saquinavir plus ritonavir, darunavir plus ritonavir, fosamprenavir, fosamprenavir plus ritonavir, elbasvir plus grazoprevir or letermovir do not exceed atorvastatin 20 mg.

Source: FDA drug label - amlodipine and atorvastatin

However, strong inhibitors of CYP3A4 (e.g., ketoconazole, itraconazole, ritonavir) may increase the plasma concentrations of amlodipine to a greater extent.

Source: FDA drug label - amlodipine besylate

Examples of CYP2D6 Inhibitors include paroxetine and fluoxetine (also serotonergic drugs), quinidine, ritonavir.

Source: FDA drug label - amphetamine sulfate

7 DRUG INTERACTIONS When co-administering ritonavir with other protease inhibitors (atazanavir, darunavir, fosamprenavir, saquinavir, and tipranavir), see the full prescribing information for that protease inhibitor including important information for drug interactions. Established and Other Potentially Significant Drug Interactions Concomitant Drug Class: Drug Name Effect on Concentration of Ritonavir or Concomitant Drug Clinical Comment HIV-Antiviral Agents HIV-1 Protease Inhibitor: atazanavir darunavir fosamprenavir ↑ amprenavir ↑ atazanavir ↑ darunavir See the complete prescribing information for fosamprenavir, atazanavir, darunavir for details on co-administration with ritonavir.

Source: FDA drug label - ritonavir

( 7.2 , 12.3 ) 7.1 Combined P-gp Strong CYP3A4 Inhibitors For patients receiving apixaban 5 mg or 10 mg twice daily, the dose of apixaban should be decreased by 50% when coadministered with drugs that are combined P-gp and strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, ritonavir) [see Dosage and Administration (2.5) and Clinical Pharmacology ( 12.3) ].

Source: FDA drug label - apixaban

7 DRUG INTERACTIONS When co-administering ritonavir with other protease inhibitors (atazanavir, darunavir, fosamprenavir, saquinavir, and tipranavir), see the full prescribing information for that protease inhibitor including important information for drug interactions. Established and Other Potentially Significant Drug Interactions Concomitant Drug Class: Drug Name Effect on Concentration of Ritonavir or Concomitant Drug Clinical Comment HIV-Antiviral Agents HIV-1 Protease Inhibitor: atazanavir darunavir fosamprenavir ↑ amprenavir ↑ atazanavir ↑ darunavir See the complete prescribing information for fosamprenavir, atazanavir, darunavir for details on co-administration with ritonavir.

Source: FDA drug label - ritonavir

Intervention: Concomitant use of tipranavir plus ritonavir or glecaprevir plus pibrentasvir with atorvastatin is not recommended. In patients taking lopinavir plus ritonavir, or simeprevir, consider the risk/benefit of concomitant use with atorvastatin. In patients taking saquinavir plus ritonavir, darunavir plus ritonavir, fosamprenavir, fosamprenavir plus ritonavir, elbasvir plus grazoprevir or letermovir, do not exceed atorvastatin 20 mg.

Source: FDA drug label - atorvastatin calcium

Ritonavir: Coadministration is not recommended. 7.2 Cytochrome P450 3A4 Ritonavir (a strong CYP3A4 inhibitor) significantly increased plasma fluticasone propionate exposure following administration of fluticasone propionate aqueous nasal spray, resulting in significantly reduced serum cortisol concentrations [see Clinical Pharmacology (12.3)] . During postmarketing use, there have been reports of clinically significant drug interactions in patients receiving fluticasone propionate and ritonavir, resulting in systemic corticosteroid effects including Cushing syndrome and adrenal suppression.

Source: FDA drug label - azelastine hydrochloride and fluticasone propionate

Examples: Macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), protease inhibitors (e.g., ritonavir) etc.

Source: FDA drug label - benzhydrocodone and acetaminophen

Inhibitors of CYP3A4 (e.g., ketoconazole, itraconazole, ritonavir, indinavir, saquinavir, erythromycin, and cyclosporine) can increase systemic budesonide concentrations [see Clinical Pharmacology (12.3) ] .

Source: FDA drug label - budesonide

ketoconazole), protease inhibitors (e.g., ritonavir) CYP3A4 Inducers Clinical Impact: The concomitant use of buprenorphine and CYP3A4 inducers can decrease the plasma concentration of buprenorphine [see Clinical Pharmacology (12.3)] , potentially resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence to buprenorphine. Examples: efavirenz, nevirapine, etravirine, delavirdine Antiretrovirals: Protease inhibitors (PIs) Clinical Impact: Studies have shown some antiretroviral protease inhibitors (PIs) with CYP3A4 inhibitory activity (nelfinavir, lopinavir/ritonavir, ritonavir) have little effect on buprenorphine pharmacokinetic and no significant pharmacodynamic effects. Other PIs with CYP3A4 inhibitory activity (atazanavir and atazanavir/ritonavir) resulted in elevated levels of buprenorphine and norbuprenorphine, and patients in one study reported increased sedation.

Source: FDA drug label - buprenorphine

ketoconazole), protease inhibitors (e.g., ritonavir) CYP3A4 Inducers Clinical Impact: The concomitant use of buprenorphine and CYP3A4 inducers can decrease the plasma concentration of buprenorphine [see Clinical Pharmacology (12.3) ] , potentially resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence to buprenorphine. Examples: efavirenz, nevirapine, etravirine, delavirdine Antiretrovirals: Protease inhibitors (PIs) Clinical Impact: Studies have shown some antiretroviral protease inhibitors (PIs) with CYP3A4 inhibitory activity (nelfinavir, lopinavir/ritonavir, ritonavir) have little effect on buprenorphine pharmacokinetic and no significant pharmacodynamic effects. Other PIs with CYP3A4 inhibitory activity (atazanavir and atazanavir/ritonavir) resulted in elevated levels of buprenorphine and norbuprenorphine, and patients in one study reported increased sedation.

Source: FDA drug label - buprenorphine and naloxone

ketoconazole), protease inhibitors (e.g., ritonavir). Intervention: Patients who are on chronic buprenorphine sublingual tablets treatment should have their dose monitored if NNRTIs are added to their treatment regimen Examples: Efavirenz, nevirapine, etravirine, delavirdine Antiretrovirals: Protease inhibitors (PIs) Clinical Impact: Studies have shown some antiretroviral protease inhibitors (PIs) with CYP3A4 inhibitory activity (nelfinavir, lopinavir/ritonavir, ritonavir) have little effect on buprenorphine pharmacokinetic and no significant pharmacodynamic effects. Other PIs with CYP3A4 inhibitory activity (atazanavir and atazanavir/ritonavir) resulted in elevated levels of buprenorphine and norbuprenorphine, and patients in one study reported increased sedation.

Source: FDA drug label - buprenorphine hydrochloride

Inducers of CYP2B6 Ritonavir, Lopinavir, and Efavirenz: Concomitant treatment with these drugs can decrease bupropion and hydroxybupropion exposure. Dosage increase of bupropion hydrochloride extended-release tablets (XL) may be necessary when coadministered with ritonavir, lopinavir, or efavirenz but should not exceed the maximum recommended dose [see CLINICAL PHARMACOLOGY (12.3)].

Source: FDA drug label - bupropion hcl er (xl)

7 DRUG INTERACTIONS CYP2B6 inducers: Dose increase may be necessary if coadministered with CYP2B6 inducers (e.g., ritonavir, lopinavir, efavirenz, carbamazepine, phenobarbital, and phenytoin) based on clinical exposure, but should not exceed the maximum recommended dose. Inducers of CYP2B6 Ritonavir, Lopinavir, and Efavirenz: Concomitant treatment with these drugs can decrease bupropion and hydroxybupropion exposure. Dosage increase of bupropion hydrochloride extended-release tablets (XL) may be necessary when coadministered with ritonavir, lopinavir, or efavirenz but should not exceed the maximum recommended dose [see Clinical Pharmacology (12.3) ].

Source: FDA drug label - bupropion hydrochloride

Other Inhibitors and Inducers of CYP3A4 Substances that inhibit CYP3A4, such as ketoconazole or ritonavir, may inhibit buspirone metabolism and increase plasma concentrations of buspirone while substances that induce CYP3A4, such as dexamethasone or certain anticonvulsants (phenytoin, phenobarbital, carbamazepine), may increase the rate of buspirone metabolism.

Source: FDA drug label - buspirone

Other inhibitors and inducers of CYP3A4: Substances that inhibit CYP3A4, such as ketoconazole or ritonavir, may inhibit buspirone metabolism and increase plasma concentrations of buspirone while substances that induce CYP3A4, such as dexamethasone or certain anticonvulsants (phenytoin, phenobarbital, carbamazepine), may increase the rate of buspirone metabolism.

Source: FDA drug label - buspirone hydrochloride

ketoconazole), protease inhibitors (e.g., ritonavir), grapefruit juice CYP3A4 Inducers Clinical Impact: The concomitant use of Butalbital, Acetaminophen, Caffeine, and Codeine Phosphate Capsules and CYP3A4 inducers can result in lower codeine levels, greater norcodeine levels, and less metabolism via 2D6 with resultant lower morphine levels [see Clinical Pharmacology (12.3) ] , resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence [see Warnings and Precautions (5.7) ] .

Source: FDA drug label - butalbital, acetaminophen, caffeine, and codeine phosphate

Rilpivirine Based on drug interaction study results, the following drugs can be coadministered with rilpivirine (non-antiretrovirals and cabotegravir) or given after discontinuation of rilpivirine (antiretrovirals and non-antiretrovirals): acetaminophen, atorvastatin, cabotegravir, chlorzoxazone, dolutegravir, ethinyl estradiol, norethindrone, raltegravir, ritonavir-boosted atazanavir, ritonavir-boosted darunavir, sildenafil, tenofovir alafenamide, and tenofovir disoproxil fumarate [see Clinical Pharmacology ( 12.3 )] .

Source: FDA drug label - cabotegravir and rilpivirine

Ritonavir Etravirine Ritonavir, Etravirine: (see Ritonavir and Etravirine under “Drugs That Affect Clarithromycin Tablets” in the table below) [see Pharmacokinetics ( 12.3 )] . Ritonavir (in patients with decreased renal function) Ritonavir: Since concentrations of 14-OH clarithromycin are significantly reduced when clarithromycin is co-administered with ritonavir, alternative antibacterial therapy should be considered for indications other than infections due to Mycobacterium avium [see Pharmacokinetics ( 12.3 )] . Saquinavir (in patients with decreased renal function) Saquinavir: When saquinavir is co-administered with ritonavir, consideration should be given to the potential effects of ritonavir on clarithromycin (refer to ritonavir above) [see Pharmacokinetics ( 12.3 )] .

Source: FDA drug label - ritonavir

Anticonvulsants: carbamazepine, clonazepam, ethosuximide ↑ anticonvulsants A dose decrease may be needed for these drugs when co-administered with ritonavir and therapeutic concentration monitoring is recommended for these anticonvulsants, if available.

Source: FDA drug label - ritonavir

ketoconazole), protease inhibitors (e.g., ritonavir) CYP3A4 Inducers Clinical Impact: The concomitant use of Codeine Sulfate Tablets and CYP3A4 inducers can result in lower codeine levels, greater norcodeine levels, and less metabolism via 2D6 with resultant lower morphine levels [see Clinical Pharmacology ( 12.3 )] , resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence [see Warnings and Precautions ( 5.7 )] .

Source: FDA drug label - codeine sulfate

Drug Interactions: Pharmacokinetic Parameters for Colchicine Tablets in the Presence of the Coadministered Drug Coadministered Drug Dose of Coadministered Drug (mg) Dose of Colchicine Tablets (mg) N % Change in Colchicine Concentrations from Baseline (Range: Min – Max) C max AUC 0-t Cyclosporine 100 mg single dose 0.6 mg single dose 23 270.0 (62.0 to 606.9) 259.0 (75.8 to 511.9) Clarithromycin 250 mg twice daily, 7 days 0.6 mg single dose 23 227.2 (65.7 to 591.1) 281.5 (88.7 to 851.6) Ketoconazole 200 mg twice daily, 5 days 0.6 mg single dose 24 101.7 (19.6 to 219.0) 212.2 (76.7 to 419.6) Ritonavir 100 mg twice daily, 5 days 0.6 mg single dose 18 184.4 (79.2 to 447.4) 296.0 (53.8 to 924.4) Verapamil 240 mg daily, 5 days 0.6 mg single dose 24 40.1 (-47.1 to 149.5) 103.3 (-9.8 to 217.2) Diltiazem 240 mg daily, 7 days 0.6 mg single dose 20 44.2 (-46.0 to 318.3) 93.4 (-30.2 to 338.6) Azithromycin 500 mg x 1 day, then 250 mg x 4 days 0.6 mg single dose 21 21.6 (-41.7 to 222.0) 57.1 (-24.3 to 241.1) Grapefruit juice 240 mL twice daily, 4 days 0.6 mg single dose 21 -2.55 (-53.4 to 55.0) -2.36 (-46.4 to 62.2) Estrogen-containing oral contraceptives: In healthy female volunteers given ethinyl estradiol and norethindrone (Ortho-Novum ® 1/35) coadministered with colchicine tablets (0.6 mg twice daily × 14 days), hormone concentrations are not affected.

Source: FDA drug label - colchicine

Drugs That Increase Cyclosporine Concentrations Calcium Channel Blockers Antifungals Antibiotics Glucocorticoids Other Drugs diltiazem fluconazole azithromycin methylprednisolone Allopurinol nicardipine itraconazole clarithromycin Amiodarone verapamil ketoconazole erythromycin Bromocriptine voriconazole quinupristin/ dalfopristin colchicine danazol imatinib metoclopramide nefazodone oral contraceptives HIV Protease inhibitors The HIV protease inhibitors (e.g., indinavir, nelfinavir, ritonavir, and saquinavir) are known to inhibit cytochrome P-450 3A and thus could potentially increase the concentrations of cyclosporine, however no formal studies of the interaction are available.

Source: FDA drug label - cyclosporine

7 DRUG INTERACTIONS Co-administration of darunavir/ritonavir with other drugs can alter the concentrations of other drugs and other drugs may alter the concentrations of darunavir. ( 4 , 5.5 , 7 , 12.3 ) 7.1 Potential for Darunavir/ritonavir to Affect Other Drugs Darunavir co-administered with ritonavir is an inhibitor of CYP3A, CYP2D6 and P-gp. Co-administration of darunavir and ritonavir with drugs that are primarily metabolized by CYP3A and CYP2D6 or are transported by P-gp may result in increased plasma concentrations of such drugs, which could increase or prolong their therapeutic effect and adverse events.

Source: FDA drug label - ritonavir

Switching from darunavir co-administered with ritonavir to PREZCOBIX in patients on bosentan : Maintain bosentan dose. Patients switching from darunavir co-administered with ritonavir to PREZCOBIX : Maintain tadalafil dose.

Source: FDA drug label - darunavir ethanolate and cobicistat

Anticancer Agents: abemaciclib, apalutamide, dasatinib, encorafenib, ibrutinib, ivosidenib, neratinib, nilotinib, venetoclax, vinblastine, vincristine ↑ anticancer agents ↓ ritonavir refers to interaction with apalutamide. A decrease in the dosage or an adjustment of the dosing interval of nilotinib and dasatinib may be necessary for patients requiring co-administration with strong CYP3A inhibitors such as ritonavir. Please refer to the nilotinib and dasatinib prescribing information for dosing instructions.

Source: FDA drug label - ritonavir

The concomitant use of deferasirox with strong UGT inducers (e.g., rifampicin, phenytoin, phenobarbital, ritonavir) may result in a decrease in deferasirox efficacy due to a possible decrease in deferasirox concentration.

Source: FDA drug label - deferasirox

Co-administration with other drugs which strongly inhibit CYP 3A4 (e.g., itraconazole, clarithromycin, ritonavir, cobicistat-containing products) may lead to increased plasma concentrations of corticosteroids and potentially increase the risk for systemic corticosteroid side effects.

Source: FDA drug label - dexamethasone

Examples of CYP2D6 inhibitors include paroxetine and fluoxetine (also serotonergic drugs), quinidine, ritonavir.

Source: FDA drug label - dextroamphetamine saccharate, amphetamine aspartate monohydrate, dextroamphetamine sulfate, and amphetamine sulfate

Examples of CYP2D6 Inhibitors include paroxetine and fluoxetine (also serotonergic drugs), quinidine, ritonavir.

Source: FDA drug label - dextroamphetamine sulfate

Sedative/hypnotics: buspirone, clorazepate, diazepam, estazolam, flurazepam, zolpidem ↑ sedative/hypnotics A dose decrease may be needed for these drugs when co-administered with ritonavir.

Source: FDA drug label - ritonavir

Captopril 58% 39% Clarithromycin NA 70% Dronedarone NA 150% Gentamicin 129-212% NA Erythromycin 100% NA Itraconazole 80% NA Lapatinib NA 180% Propafenone NA 60-270% Quinidine 100% NA Ranolazine 50% NA Ritonavir NA 86% Telaprevir 50% 85% Tetracycline 100% NA Verapamil 50-75% NA Digoxin concentrations increased less than 50% Atorvastatin 22% 15% Carvedilol 16% 14% Measure serum digoxin concentrations before initiating concomitant drugs.

Source: FDA drug label - digoxin

Therefore, increased monitoring of valproate and concomitant drug concentrations and dosage adjustment are indicated whenever enzyme-inducing or inhibiting drugs are introduced or withdrawn ( 7.1 ) • Aspirin, carbapenem antibiotics, estrogen-containing hormonal contraceptives, methotrexate: Monitoring of valproate concentrations is recommended ( 7.1 ) • Co-administration of valproate can affect the pharmacokinetics of other drugs (e.g., diazepam, ethosuximide, lamotrigine, phenytoin) by inhibiting their metabolism or protein binding displacement ( 7.2 ) • Patients stabilized on rufinamide should begin valproate therapy at a low dose, and titrate to clinically effective dose ( 7.2 ) • Dosage adjustment of amitriptyline/nortriptyline, propofol, warfarin, and zidovudine may be necessary if used concomitantly with divalproex sodium extended-release tablets ( 7.2 ) • Topiramate: Hyperammonemia and encephalopathy ( 5.10 , 7.3 ) • Cannabidiol: ALT and/or AST elevation ( 7.4 ) 7.1 Effects of Co-Administered Drugs on Valproate Clearance Drugs that affect the level of expression of hepatic enzymes, particularly those that elevate levels of glucuronosyltransferases (such as ritonavir), may increase the clearance of valproate.

Source: FDA drug label - divalproex sodium

Protease inhibitors, particularly ritonavir, may increase the exposure of docetaxel.

Source: FDA drug label - docetaxel

Protease inhibitors, particularly ritonavir, may increase the exposure of docetaxel.

Source: FDA drug label - docetaxel anhydrous

7.3 Concomitant Use with HCV Combination Therapy – Liver Enzyme Elevation Do not co-administer Yaz with HCV drug combinations containing ombitasvir/paritaprevir/ritonavir, with or without dasabuvir, due to potential for ALT elevations [see Warnings and Precautions ( 5.5 )] .

Source: FDA drug label - drospirenone and ethinyl estradiol

Fosamprenavir/ritonavir: An additional 100 mg/day (300 mg total) of ritonavir is recommended when efavirenz tablets are administered with fosamprenavir/ritonavir once daily. No change in the ritonavir dose is required when efavirenz tablets are administered with fosamprenavir plus ritonavir twice daily. Protease inhibitor: Atazanavir ↓ atazanavir * Treatment –naïve patients : When co-administered with efavirenz tablets , the recommended dose of atazanavir is 400 mg with ritonavir 100 mg (together once daily with food) and efavirenz tablets 600 mg ( once daily on an empty stomach, preferably at bedtime).

Source: FDA drug label - efavirenz

7.3 Protease Inhibitors HIV Protease Inhibitors: No dose adjustment is recommended when eltrombopag is co-administered with lopinavir/ritonavir (LPV/RTV).

Source: FDA drug label - eltrombopag

Drug Interactions Concomitant Drug Class: Drug Name Effect on Concentration ↓=Decrease Clinical Comment ↑= Increase Antiretroviral Agents: Protease Inhibitors (PI) tipranavir/ritonavir ↓ TAF Coadministration with DESCOVY is not recommended. 7.4 Drugs without Clinically Significant Interactions with DESCOVY Based on drug interaction studies conducted with the components of DESCOVY, no clinically significant drug interactions have been either observed or are expected when DESCOVY is combined with the following antiretroviral agents: atazanavir with ritonavir, atazanavir with cobicistat (in those weighing ≥35 kg), darunavir with ritonavir or cobicistat, dolutegravir, efavirenz, ledipasvir, lopinavir/ritonavir, maraviroc, nevirapine, raltegravir, rilpivirine, and sofosbuvir.

Source: FDA drug label - emtricitabine and tenofovir alafenamide

7.17 Ritonavir Combined administration of a single dose of ritonavir (600 mg), both a CYP3A4 substrate and a potent inhibitor of CYP3A4, and escitalopram (20 mg) did not affect the pharmacokinetics of either ritonavir or escitalopram. However, coadministration of escitalopram (20 mg) and ritonavir (600 mg), a potent inhibitor of CYP3A4, did not significantly affect the pharmacokinetics of escitalopram.

Source: FDA drug label - escitalopram

7.17 Ritonavir Combined administration of a single dose of ritonavir (600 mg), both a CYP3A4 substrate and a potent inhibitor of CYP3A4, and escitalopram (20 mg) did not affect the pharmacokinetics of either ritonavir or escitalopram. However, coadministration of escitalopram (20 mg) and ritonavir (600 mg), a potent inhibitor of CYP3A4, did not significantly affect the pharmacokinetics of escitalopram.

Source: FDA drug label - escitalopram oxalate

Ritonavir-containing products: see prescribing information for specific drugs Voriconazole Clinical Impact: Increased exposure of esomeprazole [see Clinical Pharmacology (12.3) ].

Source: FDA drug label - esomeprazole magnesium

Sedative/hypnotics: buspirone, clorazepate, diazepam, estazolam, flurazepam, zolpidem ↑ sedative/hypnotics A dose decrease may be needed for these drugs when co-administered with ritonavir.

Source: FDA drug label - ritonavir

Inhibitors of CYP3A4 such as erythromycin, clarithromycin, ketoconazole, itraconazole, ritonavir, and grapefruit juice may increase plasma concentrations of estrogens and may result in adverse reactions.

Source: FDA drug label - estradiol

Inhibitors of CYP3A4 such as erythromycin, clarithromycin, ketoconazole, itraconazole, ritonavir and grapefruit juice may increase plasma concentrations of estrogens and may result in adverse reactions.

Source: FDA drug label - estradiol and levonorgestrel

Other strong inhibitors of CYP3A4 (e.g., itraconazole, clarithromycin, nefazodone, troleandomycin, ritonavir, nelfinavir) would be expected to behave similarly.

Source: FDA drug label - eszopiclone

Anticonvulsants: carbamazepine, clonazepam, ethosuximide ↑ anticonvulsants A dose decrease may be needed for these drugs when co-administered with ritonavir and therapeutic concentration monitoring is recommended for these anticonvulsants, if available.

Source: FDA drug label - ritonavir

Human immunodeficiency virus (HIV) / Hepatitis C Virus (HCV) protease inhibitors and nonnucleoside reverse transcriptase inhibitors Significant changes in the plasma concentrations of the estrogen and /or progestin have been noted in some cases of co-administration with HIV protease inhibitors (decrease [e.g., nelfinavir, ritonavir, darunavir/ritonavir, (fos)amprenavir/ritonavir, lopinavir/ritonavir, and tipranavir/ritonavir] or increase [e.g., indinavir and atazanavir/ritonavir]) /HCV protease inhibitors (decrease [e.g., boceprevir and telaprevir]) or with non-nucleoside reverse transcriptase inhibitors (decrease [e.g., efavirenz, nevirapine] or increase [e.g., etravirine]). 7.3 Concomitant Use with HCV Combination Therapy – Liver Enzyme Elevation Do not co-administer etonogestrel and ethinyl estradiol vaginal ring with HCV drug combinations containing ombitasvir/paritaprevir/ritonavir, with or without dasabuvir, due to potential for ALT elevations.

Source: FDA drug label - etonogestrel and ethinyl estradiol vaginal ring

dolutegravir/darunavir/ritonavir ↓ dolutegravir ↔ etravirine The effect of etravirine on dolutegravir plasma concentrations was mitigated by co- administration of darunavir/ritonavir or lopinavir/ritonavir, and is expected to be mitigated by atazanavir/ritonavir. dolutegravir/lopinavir/ritonavir ↔ dolutegravir ↔ etravirine Dolutegravir should only be used with etravirine tablets when co- administered with atazanavir/ritonavir, darunavir/ritonavir, or lopinavir/ritonavir. HIV-antiviral agents: protease inhibitors (PIs) atazanavir (without ritonavir) atazanavir/ritonavir atazanavir/cobicistat darunavir/ritonavir darunavir/cobicistat fosamprenavir (without ritonavir) fosamprenavir/ritonavir indinavir (without ritonavir) lopinavir/ritonavir ↓ atazanavir ↓ atazanavir ↔ etravirine ↓ atazanavir ↓ cobicistat ↓ etravirine ↓ cobicistat darunavir: effect unknown ↑ amprenavir ↑ amprenavir ↓ indinavir ↓ etravirine Co-administration of etravirine tablets and atazanavir without low- dose ritonavir is not recommended.

Source: FDA drug label - etravirine

Table 1: Drugs That Affect Phenytoin Concentrations Interacting Agent Examples Drugs that may increase phenytoin serum levels Antiepileptic drugs Ethosuximide, felbamate, oxcarbazepine, methsuximide, topiramate Azoles Fluconazole, ketoconazole, itraconazole, miconazole, voriconazole Antineoplastic agents Capecitabine, fluorouracil Antidepressants Fluoxetine, fluvoxamine, sertraline Gastric acid reducing agents H 2 antagonists (cimetidine), omeprazole Sulfonamides Sulfamethizole, sulfaphenazole, sulfadiazine, sulfamethoxazole trimethoprim Other Acute alcohol intake, amiodarone, chloramphenicol, chlordiazepoxide, disulfiram, estrogen, fluvastatin, isoniazid, methylphenidate, phenothiazines, salicylates, ticlopidine, tolbutamide, trazodone, warfarin Drugs that may decrease phenytoin serum levels Antineoplastic agents usually in combination Bleomycin, carboplatin, cisplatin, doxorubicin, methotrexate Antiviral agents Fosamprenavir, nelfinavir, ritonavir Antiepileptic drugs Carbamazepine, vigabatrin Other Chronic alcohol abuse, diazepam, diazoxide, folic acid, reserpine, rifampin, St. Warfarin Increased and decreased PT/INR responses have been reported when phenytoin is coadministered with warfarin Other Corticosteroids, doxycycline, estrogens, furosemide, oral contraceptives, paroxetine, quinidine, rifampin, sertraline, theophylline, and vitamin D Drugs whose level is decreased by phenytoin Antiepileptic drugs a Carbamazepine, felbamate, lamotrigine, topiramate, oxcarbazepine Antilipidemic agents Atorvastatin, fluvastatin, simvastatin Antiviral agents Efavirenz, lopinavir/ritonavir, indinavir, nelfinavir, ritonavir, saquinavir Fosamprenavir: phenytoin when given with fosamprenavir alone may decrease the concentration of amprenavir, the active metabolite. Phenytoin when given with the combination of fosamprenavir and ritonavir may increase the concentration of amprenavir Calcium channel blockers Nifedipine, nimodipine, nisoldipine, verapamil Other Albendazole (decreases active metabolite), chlorpropamide, clozapine, cyclosporine, digoxin, disopyramide, folic acid, methadone, mexiletine, praziquantel, quetiapine a The effect of phenytoin on phenobarbital, valproic acid and sodium valproate serum levels is unpredictable 7.3 Drug/Laboratory Test Interactions Care should be taken when using immunoanalytical methods to measure serum phenytoin concentrations following fosphenytoin administration.

Source: FDA drug label - extended phenytoin sodium

ketoconazole), protease inhibitors (e.g., ritonavir), grapefruit juice CYP3A4 Inducers Clinical Impact: The concomitant use of Fentanyl Citrate Injection and CYP3A4 inducers can decrease the plasma concentration of fentanyl [see Clinical Pharmacology ( 12.3 )] , resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence to fentanyl [see Warnings and Precautions ( 5.4 )] .

Source: FDA drug label - fentanyl citrate

Sedative/hypnotics: buspirone, clorazepate, diazepam, estazolam, flurazepam, zolpidem ↑ sedative/hypnotics A dose decrease may be needed for these drugs when co-administered with ritonavir.

Source: FDA drug label - ritonavir

7 DRUG INTERACTIONS Strong cytochrome P450 3A4 inhibitors (e.g., ritonavir, ketoconazole): Use not recommended. The use of strong CYP3A4 inhibitors (e.g., ritonavir, atazanavir, clarithromycin, indinavir, itraconazole, nefazodone, nelfinavir, saquinavir, ketoconazole, telithromycin) with FLOVENT DISKUS is not recommended because increased systemic corticosteroid adverse effects may occur. Ritonavir A drug interaction trial with fluticasone propionate aqueous nasal spray in healthy subjects has shown that ritonavir (a strong CYP3A4 inhibitor) can significantly increase plasma fluticasone propionate exposure, resulting in significantly reduced serum cortisol concentrations [see Clinical Pharmacology (12.3)] .

Source: FDA drug label - fluticasone propionate

• Strong Cytochrome P450 3A4 Inhibitors (e.g., ritonavir, ketoconazole): Use not recommended. The use of strong CYP3A4 inhibitors (e.g., ritonavir, atazanavir, clarithromycin, indinavir, itraconazole, nefazodone, nelfinavir, saquinavir, ketoconazole, telithromycin) with fluticasone propionate and salmeterol inhalation powder is not recommended because increased systemic corticosteroid and increased cardiovascular adverse effects may occur. Ritonavir Fluticasone Propionate: A drug interaction trial with fluticasone propionate aqueous nasal spray in healthy subjects has shown that ritonavir (a strong CYP3A4 inhibitor) can significantly increase plasma fluticasone propionate exposure, resulting in significantly reduced serum cortisol concentrations [see Clinical Pharmacology ( )] .

Source: FDA drug label - fluticasone propionate and salmeterol

7 DRUG INTERACTIONS When co-administering ritonavir with other protease inhibitors (atazanavir, darunavir, fosamprenavir, saquinavir, and tipranavir), see the full prescribing information for that protease inhibitor including important information for drug interactions. Established and Other Potentially Significant Drug Interactions Concomitant Drug Class: Drug Name Effect on Concentration of Ritonavir or Concomitant Drug Clinical Comment HIV-Antiviral Agents HIV-1 Protease Inhibitor: atazanavir darunavir fosamprenavir ↑ amprenavir ↑ atazanavir ↑ darunavir See the complete prescribing information for fosamprenavir, atazanavir, darunavir for details on co-administration with ritonavir.

Source: FDA drug label - ritonavir

Hepatitis C direct acting antiviral: glecaprevir/pibrentasvir simeprevir ↑ glecaprevir ↑ pibrentasvir ↑ simeprevir It is not recommended to co-administer ritonavir with glecaprevir/pibrentasvir, or simeprevir.

Source: FDA drug label - ritonavir

Examples include: CYP3A4 inhibitors - alprazolam; itraconazole, ketoconazole, nefazodone, ritonavir. Combined CYP3A4 and CYP2D6 inhibitors - fluoxetine, fluvoxamine; ritonavir.

Source: FDA drug label - haloperidol decanoate

Drug Interactions Inhibitors of CYP3A4 and CYP2D6 The concomitant use of hydrocodone bitartrate and acetaminophen tablets and CYP3A4 inhibitors, such as macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), and protease inhibitors (e.g., ritonavir), can increase the plasma concentration of the hydrocodone from hydrocodone bitartrate and acetaminophen tablets, resulting in increased or prolonged opioid effects.

Source: FDA drug label - hydrocodone bitartrate and acetaminophen

ketoconazole), or protease inhibitors (e.g., ritonavir), can increase the plasma concentration of hydrocodone, resulting in increased or prolonged opioid effects.

Source: FDA drug label - hydrocodone polistirex and chlorpheniramine polistirex

HIV-1 Protease Inhibitor: indinavir ↑ indinavir Appropriate doses for this combination, with respect to efficacy and safety, have not been established.

Source: FDA drug label - ritonavir

Antifungals: ketoconazole itraconazole voriconazole ↑ ketoconazole ↑ itraconazole ↓ voriconazole High doses of ketoconazole or itraconazole (greater than 200 mg per day) are not recommended.

Source: FDA drug label - ritonavir

Antifungals: ketoconazole itraconazole voriconazole ↑ ketoconazole ↑ itraconazole ↓ voriconazole High doses of ketoconazole or itraconazole (greater than 200 mg per day) are not recommended.

Source: FDA drug label - ritonavir

Lopinavir/ritonavir ↓ lamotrigine Decreased lamotrigine concentration approximately 50%. Atazanavir/ritonavir ↓ lamotrigine Decreased lamotrigine AUC approximately 32%. ( 7 , 12.3 ) Protease inhibitors lopinavir/ritonavir and atazanavir/lopinavir decrease lamotrigine exposure by approximately 50% and 32%, respectively.

Source: FDA drug label - lamotrigine

Ritonavir-containing products : See prescribing information.

Source: FDA drug label - lansoprazole

7.2 Ritonavir Ritonavir increased the plasma AUC of cetirizine by about 42% accompanied by an increase in half-life (53%) and a decrease in clearance (29%) of cetirizine. The disposition of ritonavir was not altered by concomitant cetirizine administration.

Source: FDA drug label - levocetirizine dihydrochloride

Human immunodeficiency virus (HIV)/ Hepatitis C virus (HCV) protease inhibitors and non-nucleoside reverse transcriptase inhibitors: Significant changes (increase or decrease) in the plasma concentrations of estrogen and/or progestin have been noted in some cases of co-administration with HIV/HCV protease inhibitors and non-nucleoside reverse transcriptase inhibitors (decrease [e.g., nelfinavir, ritonavir, darunavir/ritonavir, (fos)amprenavir/ritonavir, lopinavir/ritonavir, tipranavir/ritonavir, boceprevir, telaprevir, nevirapine and efavirenz] or increase [e.g., indinavir, atazanavir/ritonavir and etravirine]). 7.3 Concomitant Use with HCV Combination Therapy - Liver Enzyme Elevation Do not co-administer levonorgestrel and ethinyl estradiol tablets and ferrous bisglycinate tablets with HCV drug combinations containing ombitasvir/ paritaprevir/ritonavir, with or without dasabuvir, due to potential for ALT elevations [see Warnings and Precautions ( 5.3 )] .

Source: FDA drug label - levonorgestrel and ethinyl estradiol

Co-administration of other strong CYP3A4 inhibitors (e.g., ritonavir, atazanavir, clarithromycin, indinavir, itraconazole, nefazodone, nelfinavir, saquinavir, telithromycin, cobicistat-containing products) with triamcinolone acetonide injectable suspension may cause increased plasma concentration of triamcinolone leading to adverse reactions (see ADVERSE REACTIONS ). During postmarketing use, there have been reports of clinically significant drug interactions in patients receiving triamcinolone acetonide and strong CYP3A4 inhibitors (e.g., ritonavir) (see WARNINGS, Endocrine and PRECAUTIONS, Endocrine ).

Source: FDA drug label - lidocaine hydrochloride, triamcinolone acetonide, povidone-iodine

7 DRUG INTERACTIONS Co-administration of lopinavir and ritonavir can alter the plasma concentrations of other drugs and other drugs may alter the plasma concentrations of lopinavir. ( 4 , 5.1 , 7 , 12.3 ) 7.1 Potential for Lopinavir And Ritonavir to Affect Other Drugs Lopinavir/ritonavir is an inhibitor of CYP3A and may increase plasma concentrations of agents that are primarily metabolized by CYP3A. Agents that are extensively metabolized by CYP3A and have high first pass metabolism appear to be the most susceptible to large increases in AUC (> 3-fold) when co-administered with lopinavir and ritonavir.

Source: FDA drug label - lopinavir and ritonavir

7 DRUG INTERACTIONS • Coadministration with CYP3A inhibitors, including protease inhibitors (except tipranavir/ritonavir), will increase the concentration of maraviroc.

Source: FDA drug label - maraviroc

Co-administration of other strong CYP3A4 inhibitors (e.g., ritonavir, atazanavir, clarithromycin, indinavir, itraconazole, nefazodone, nelfinavir, saquinavir, telithromycin, cobicistat-containing products) with triamcinolone acetonide injectable suspension may cause increased plasma concentration of triamcinolone leading to adverse reactions (see ADVERSE REACTIONS ). During postmarketing use, there have been reports of clinically significant drug interactions in patients receiving triamcinolone acetonide and strong CYP3A4 inhibitors (e.g., ritonavir) (see WARNINGS, Endocrine and PRECAUTIONS, Endocrine ).

Source: FDA drug label - marcaine, kenalog, povidone iodine

Examples: Macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), protease inhibitors (e.g., ritonavir) CYP3A4 and CYP2B6 Inducers Clinical Impact: The concomitant use of meperidine and CYP3A4 or CYP2B6 inducers can decrease the plasma concentration of meperidine [see Clinical Pharmacology ( 12.3 )], resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence to meperidine [see Warnings and Precautions ( 5.7 )].

Source: FDA drug label - meperidine hydrochloride

Examples: Macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), protease inhibitors (e.g., ritonavir), fluconazole, fluvoxamine, some selective serotonin reuptake inhibitors (SSRIs) (e.g., sertraline, fluvoxamine) Inducers of CYP3A4, CYP2B6, CYP2C19, or CYP2C9 Clinical Impact: The concomitant use of methadone and CYP3A4, CYP2B6, CYP2C19, or CYP2C9 inducers can decrease the plasma concentration of methadone [see Clinical Pharmacology ( 12.3 )] , resulting in decreased efficacy or onset of withdrawal symptoms in patients physically dependent on methadone. Paradoxical Effects of Anti-Retroviral Agents on Methadone Concurrent use of certain protease inhibitors with CYP3A4 inhibitory activity, alone and in combination, such as abacavir, amprenavir, darunavir+ritonavir, efavirenz, nelfinavir, nevirapine, ritonavir, telaprevir, lopinavir+ritonavir, saquinavir+ritonavir, and tipranvir+ritonavir, has resulted in increased clearance or decreased plasma levels of methadone.

Source: FDA drug label - methadone hydrochloride

Examples of some of the more potent CYP 3A4 inhibitors include macrolide antibiotics (e.g., erythromycin, troleandomycin, clarithromycin), HIV protease or reverse transcriptase inhibitors (e.g., ritonavir, indinavir, nelfinavir, delavirdine) or azole antifungals (e.g., ketoconazole, itraconazole, voriconazole).

Source: FDA drug label - methylergonovine maleate

Systemic/Inhaled/ Nasal/Ophthalmic Corticosteroids: e.g., betamethasone budesonide ciclesonide dexamethasone fluticasone methylprednisolone mometasone prednisone triamcinolone ↑ glucocorticoids Coadministration with corticosteroids whose exposures are significantly increased by strong CYP3A inhibitors can increase the risk for Cushing’s syndrome and adrenal suppression.

Source: FDA drug label - ritonavir

Known clinically significant potent inhibitors of CYP2D6 are antidepressants such as fluvoxamine, fluoxetine, paroxetine, sertraline, bupropion, clomipramine and desipramine; antipsychotics such as chlorpromazine, fluphenazine, haloperidol and thioridazine; antiarrhythmics such as quinidine or propafenone; antiretrovirals such as ritonavir; antihistamines such as diphenhydramine; antimalarials such as hydroxychloroquine or quinidine; antifungals such as terbinafine.

Source: FDA drug label - metoprolol tartrate

Antialcoholics: disulfiram/ metronidazole Ritonavir formulations contain ethanol, which can produce disulfiram-like reactions when co-administered with disulfiram or other drugs that produce this reaction (e.g., metronidazole).

Source: FDA drug label - ritonavir

Although not studied, the potent cytochrome P450 3A4 inhibitors ritonavir and nelfinavir may cause intense and prolonged sedation and respiratory depression due to a decrease in plasma clearance of midazolam.

Source: FDA drug label - midazolam hydrochloride

Examples itraconazole, ritonavir, nefazodone Cimetidine Clinical Impact The concomitant use of cimetidine, a CYP1A2, CYP2D6, and CYP3A inhibitor, with mirtazapine may increase the plasma concentration of mirtazapine [see Clinical Pharmacology (12.3) ].

Source: FDA drug label - mirtazapine

CYP3A Inhibitors CYP3A inhibitors such as ketoconazole, fluconazole, itraconazole, clarithromycin, erythromycin (Azithromycin, although structurally related to the class of macrolide antibiotic is void of clinically relevant CYP3A4 inhibition), grapefruit, nefazodone, fluoxetine, saquinavir, indinavir, nelfinavir, and ritonavir may result in increased exposure to nifedipine when co-administered.

Source: FDA drug label - ritonavir

Anticancer Agents: abemaciclib, apalutamide, dasatinib, encorafenib, ibrutinib, ivosidenib, neratinib, nilotinib, venetoclax, vinblastine, vincristine ↑ anticancer agents ↓ ritonavir refers to interaction with apalutamide. A decrease in the dosage or an adjustment of the dosing interval of nilotinib and dasatinib may be necessary for patients requiring co-administration with strong CYP3A inhibitors such as ritonavir. Please refer to the nilotinib and dasatinib prescribing information for dosing instructions.

Source: FDA drug label - ritonavir

Human Immunodeficiency Virus (HIV)/Hepatitis C Virus (HCV) Protease Inhibitors and Non-Nucleoside Reverse Transcriptase Inhibitors Significant changes (increase or decrease) in the plasma concentrations of estrogen and/or progestin have been noted in some cases of co-administration with HIV protease inhibitors (decrease [e.g., nelfinavir, ritonavir, darunavir/ritonavir, (fos)amprenavir/ritonavir, lopinavir/ritnoavir, and tipranavir/ritonavir] or increase [e.g., indinavir and atazanavir/ritonavir])/HCV protease inhibitors or with non-nucleoside reverse transcriptase inhibitors (decrease [e.g., nevirapine] or increase [e.g., etravirine]). 7.3 Concomitant Use with HCV Combination Therapy – Liver Enzyme Elevation Do not co-administer norelgestromin and ethinyl estradiol transdermal system with HCV drug combinations containing ombitasvir/paritaprevir/ritonavir, with or without dasabuvir, due to potential for ALT elevations [see Warnings and Precautions ( 5.4 )].

Source: FDA drug label - norelgestromin and ethinyl estradiol

Human Immunodeficiency Virus (HIV)/Hepatitis C Virus (HCV) protease inhibitors and nonnucleoside reverse transcriptase inhibitors: Significant decreases in systemic concentrations of progestin have been noted in cases of co-administration with some HIV protease inhibitors (e.g., nelfinavir, ritonavir, darunavir/ritonavir, (fos)amprenavir/ritonavir, lopinavir/ritonavir, and tipranavir/ritonavir), some HCV protease inhibitors (e.g., boceprevir and telaprevir), and some non-nucleoside reverse transcriptase inhibitors (e.g., nevirapine, efavirenz). In contrast, significant increases in systemic exposure of the progestin have been noted in cases of co-administration with certain other HIV protease inhibitors (e.g., indinavir and atazanavir/ritonavir) and with other non-nucleoside reverse transcriptase inhibitors (e.g., etravirine).

Source: FDA drug label - norethindrone

Human Immunodeficiency Virus (HIV)/Hepatitis C Virus (HCV) Protease Inhibitors and Non-Nucleoside Reverse Transcriptase Inhibitors Significant changes (increase or decrease) in the plasma concentrations of estrogen and/or progestin have been noted in some cases of co-administration with HIV protease inhibitors (decrease [e.g., nelfinavir, ritonavir, darunavir/ritonavir, (fos)amprenavir/ritonavir, lopinavir/ritnoavir, and tipranavir/ritonavir] or increase [e.g., indinavir and atazanavir/ritonavir])/HCV protease inhibitors or with non-nucleoside reverse transcriptase inhibitors (decrease [e.g., nevirapine] or increase [e.g., etravirine]).

Source: FDA drug label - norethindrone acetate and ethinyl estradiol

76 Concomitant Use with HCV Combination Therapy – Liver Enzyme Elevation Do not coadminister Aranelle ® with HCV drug combinations containing ombitasvir/paritaprevir/ritonavir, with or without dasabuvir, due to potential for ALT elevations (see WARNINGS, Risk of Liver Enzyme Elevations with Concomitant Hepatitis C Treatment ).

Source: FDA drug label - norethindrone and ethinyl estradiol

Human immunodeficiency virus (HIV)/Hepatitis C virus (HCV) protease inhibitors, non-nucleoside reverse transcriptase inhibitors, and HIV/AIDS medications containing strong inhibitors or inducers of CYP3A Significant changes (increase or decrease) in the plasma concentrations of estrogen and/or progestin have been noted in some cases of coadministration with HIV protease inhibitors (decrease [e.g., nelfinavir, ritonavir, darunavir/ritonavir, (fos)amprenavir/ritonavir, lopinavir/ritonavir, and tipranavir/ritonavir] or increase [e.g., indinavir and atazanavir/ritonavir])/HCV protease inhibitors (decrease [e.g., boceprevir and telaprevir]) or with non-nucleoside reverse transcriptase inhibitors (decrease [e.g., nevirapine] or increase [e.g., etravirine]) or with HIV/AIDS medications containing strong inhibitors (e.g., cobicistat and ritonavir) or inducers of CYP3A. 7.4 Concomitant Use with HCV Combination Therapy – Liver Enzyme Elevation Do not coadminister Sprintec with HCV drug combinations containing ombitasvir/paritaprevir/ritonavir, with or without dasabuvir, due to potential for ALT elevations [see Warnings and Precautions ( 5.3 )].

Source: FDA drug label - norgestimate and ethinyl estradiol

Ritonavir-containing products: see prescribing information for specific drugs.

Source: FDA drug label - omeprazole

Ritonavir-containing products: See prescribing information for specific drugs.

Source: FDA drug label - omeprazole, sodium bicarbonate

Examples: Macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), protease inhibitors (e.g., ritonavir).

Source: FDA drug label - oxycodone

ketoconazole), and protease inhibitors (e.g., ritonavir), can increase the plasma concentration of oxycodone, resulting in increased or prolonged opioid effects.

Source: FDA drug label - oxycodone and acetaminophen

Examples: Macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), protease inhibitors (e.g., ritonavir).

Source: FDA drug label - oxycodone hydrochloride

ketoconazole), protease inhibitors (e.g., ritonavir) CYP3A4 Inducers Clinical Impact: The concomitant use of Oxycodone Hydrochloride Oral Solution and CYP3A4 inducers can decrease the plasma concentration of oxycodone [see Clinical Pharmacology (12.3) ], resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence to oxycodone [see Warnings and Precautions (5.6) ].

Source: FDA drug label - oxycodone hydrochloride oral solution

Hence, exposure of paricalcitol will increase upon coadministration with strong CYP3A inhibitors such as but not limited to: boceprevir, clarithromycin, conivaptan, grapefruit juice, indinavir, itraconazole, ketoconazole, lopinavir/ritonavir, mibefradil, nefazodone, nelfinavir, posaconazole, ritonavir, saquinavir, telaprevir, telithromycin, voriconazole.

Source: FDA drug label - paricalcitol

Fosamprenavir/Ritonavir Clinical Impact Co-administration of fosamprenavir/ritonavir with paroxetine significantly decreased plasma levels of paroxetine.

Source: FDA drug label - paroxetine

Fosamprenavir/Ritonavir Clinical Impact Co-administration of fosamprenavir/ritonavir with paroxetine significantly decreased plasma levels of paroxetine.

Source: FDA drug label - paroxetine hydrochloride

Calcium carbonate, aluminum hydroxide, magnesium hydroxide Prevention or Management: Phenytoin and antacids should not be taken at the same time of day Antineoplastic agents (usually in combination) Bleomycin, carboplatin, cisplatin, doxorubicin, methotrexate Antiviral agents Fosamprenavir, nelfinavir, ritonavir Antiepileptic drugs Carbamazepine, vigabatrin Other Chronic alcohol abuse, diazepam, diazoxide, folic acid, reserpine, rifampin, St. Warfarin Increased and decreased PT/INR responses have been reported when phenytoin is coadministered with warfarin Other Corticosteroids, doxycycline, estrogens, furosemide, oral contraceptives, paroxetine, quinidine, rifampin, sertraline, theophylline, and vitamin D Drugs whose level is decreased by phenytoin Antiepileptic drugs The effect of phenytoin on phenobarbital, valproic acid and sodium valproate serum levels is unpredictable Carbamazepine, felbamate, lamotrigine, topiramate, oxcarbazepine Antilipidemic agents Atorvastatin, fluvastatin, simvastatin Antiviral agents Efavirenz, lopinavir/ritonavir, indinavir, nelfinavir, ritonavir, saquinavir Fosamprenavir: phenytoin when given with fosamprenavir alone may decrease the concentration of amprenavir, the active metabolite. Phenytoin when given with the combination of fosamprenavir and ritonavir may increase the concentration of amprenavir Calcium channel blockers Nifedipine, nimodipine, nisoldipine, verapamil Other Albendazole (decreases active metabolite), chlorpropamide, clozapine, cyclosporine, digoxin, disopyramide, folic acid, methadone, mexiletine, praziquantel, quetiapine 7.3 Drug Enteral Feeding/Nutritional Preparations Interaction Literature reports suggest that patients who have received enteral feeding preparations and/or related nutritional supplements have lower than expected phenytoin serum levels.

Source: FDA drug label - phenytoin

Hepatitis C direct acting antiviral: glecaprevir/pibrentasvir simeprevir ↑ glecaprevir ↑ pibrentasvir ↑ simeprevir It is not recommended to co-administer ritonavir with glecaprevir/pibrentasvir, or simeprevir.

Source: FDA drug label - ritonavir

Ritonavir and Atazanavir: Ritonavir and atazanavir are metabolized by CYP3A4 and posaconazole increases plasma concentrations of these drugs [ see Clinical Pharmacology (12.3) ]. Frequent monitoring of adverse effects and toxicity of ritonavir and atazanavir should be performed during coadministration with posaconazole.

Source: FDA drug label - posaconazole

Systemic/Inhaled/ Nasal/Ophthalmic Corticosteroids: e.g., betamethasone budesonide ciclesonide dexamethasone fluticasone methylprednisolone mometasone prednisone triamcinolone ↑ glucocorticoids Coadministration with corticosteroids whose exposures are significantly increased by strong CYP3A inhibitors can increase the risk for Cushing’s syndrome and adrenal suppression. Alternative corticosteroids including beclomethasone and prednisolone (whose PK and/or PD are less affected by strong CYP3A inhibitors relative to other studied steroids) should be considered, particularly for long-term use.

Source: FDA drug label - ritonavir

Drugs which inhibit CYP 3A4 (e.g., ketoconazole, itraconazole, ritonavir, indinavir, macrolide antibiotics such as erythromycin ) have the potential to result in increased plasma concentrations of corticosteroids. Drugs which inhibit CYP 3A4 (e.g., ketoconazole, itraconazole, ritonavir, indinavir, macrolide antibiotics such as erythromycin ) have the potential to result in increased plasma concentrations of corticosteroids.

Source: FDA drug label - prednisone

(7.6) 7.1 CYP2D6 and CYP3A4 Inhibitors Drugs that inhibit CYP2D6 (such as desipramine, paroxetine, ritonavir, sertraline) and CYP3A4 (such as ketoconazole, ritonavir, saquinavir, erythromycin, grapefruit juice) can be expected to cause increased plasma levels of propafenone.

Source: FDA drug label - propafenone hydrochloride

Substrates or Inhibitors of CYP2D6 Blood levels and/or toxicity of propranolol may be increased by co-administration with substrates or inhibitors of CYP2D6, such as amiodarone, cimetidine, delavudin, fluoxetine, paroxetine, quinidine, and ritonavir. Substrates or Inhibitors of CYP1A2 Blood levels and/or toxicity of propranolol may be increased by co-administration with substrates or inhibitors of CYP1A2, such as imipramine, cimetidine, ciprofloxacin, fluvoxamine, isoniazid, ritonavir, theophylline, zileuton, zolmitriptan, and rizatriptan. Substrates or Inhibitors of CYP2D6 Blood levels and/or toxicity of propranolol may be increased by co-administration with substrates or inhibitors of CYP2D6, such as amiodarone, cimetidine, delavudin, fluoxetine, paroxetine, quinidine, and ritonavir.

Source: FDA drug label - propranolol hydrochloride

7 DRUG INTERACTIONS Concomitant use of strong CYP3A4 inhibitors: Reduce quetiapine dose to one sixth when coadministered with strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir) ( 2.5 , 7.1 , 12.3 ) Concomitant use of strong CYP3A4 inducers: Increase quetiapine dose up to 5 fold when used in combination with a chronic treatment (more than 7-14 days) of potent CYP3A4 inducers (e.g., phenytoin, rifampin, St. Quetiapine exposure is increased by the prototype CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, indinavir, ritonavir, nefazodone, etc.) and decreased by the prototype CYP3A4 inducers (e.g., phenytoin, carbamazepine, rifampin, avasimibe, St.

Source: FDA drug label - quetiapine

ketoconazole, ritonavir) ( 7.1 , 12.3 ) Concomitant Use of Strong CYP3A4 Inducers: Increase quetiapine dose up to 5 fold when used in combination with a chronic treatment (more than 7 to 14 days) of potent CYP3A4 inducers (e.g. Quetiapine exposure is increased by the prototype CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, indinavir, ritonavir, nefazodone, etc.) and decreased by the prototype CYP3A4 inducers (e.g, phenytoin, carbamazepine, rifampin, avasimibe, St.

Source: FDA drug label - quetiapine fumarate

Integrase Inhibitor: raltegravir ↓ raltegravir The effects of ritonavir on raltegravir with ritonavir dosage regimens greater than 100 mg twice daily have not been evaluated, however raltegravir concentrations may be decreased with ritonavir coadministration.

Source: FDA drug label - ritonavir

Drugs that could increase sirolimus blood concentrations: Bromocriptine, cimetidine, cisapride, clotrimazole, danazol, diltiazem, fluconazole, letermovir, protease inhibitors (e.g., HIV and hepatitis C that include drugs such as ritonavir, indinavir, boceprevir, and telaprevir), metoclopramide, nicardipine, troleandomycin, verapamil Drugs and other agents that could decrease sirolimus concentrations: Carbamazepine, phenobarbital, phenytoin, rifapentine, St.

Source: FDA drug label - sirolimus

HIV-Antiviral Agents: Protease Inhibitors (PIs)-Boosted (i.e., with coadministration of low-dose ritonavir) or Unboosted (i.e., without coadministration of low-dose ritonavir) darunavir/ritonavir ↑ rilpivirine ↔ boosted darunavir Concomitant use of EDURANT or EDURANT PED with darunavir/ritonavir may cause an increase in the plasma concentrations of rilpivirine (inhibition of CYP3A enzymes). No dose adjustment is required when EDURANT or EDURANT PED is coadministered with darunavir/ritonavir. Lopinavir/ritonavir ↑ rilpivirine ↔ boosted lopinavir Concomitant use of EDURANT or EDURANT PED with lopinavir/ritonavir may cause an increase in the plasma concentrations of rilpivirine (inhibition of CYP3A enzymes).

Source: FDA drug label - rilpivirine hydrochloride

( 2.4 , 5.1 , 7.2 ) Atazanavir/ritonavir, lopinavir/ritonavir, simeprevir or combination of dasabuvir/ombitasvir/paritaprevir/ritonavir, elbasvir/grazoprevir, sofosbuvir/velpatasvir and glecaprevir/pibrentasvir: Combination increases rosuvastatin exposure. Simeprevir and combinations of dasabuvir/ombitasvir/paritaprevir/ritonavir, elbasvir/grazoprevir, sofosbuvir/velpatasvir and glecaprevir/pibrentasvir which are anti-HCV drugs, increase rosuvastatin exposure. Combinations of atazanavir/ritonavir and lopinavir/ritonavir, which are anti-HIV-1 drugs, increase rosuvastatin exposure [ see Table 4 – Clinical Pharmacology (12.3) ].

Source: FDA drug label - ritonavir

Simeprevir Dasabuvir/ombitasvir/paritaprevir/ritonavir Elbasvir/grazoprevir Sofosbuvir/velpatasvir Glecaprevir/pibrentasvir Atazanavir/ritonavir Lopinavir/ritonavir Initiate with rosuvastatin 5 mg once daily, and do not exceed a dose of rosuvastatin 10 mg once daily.

Source: FDA drug label - rosuvastatin calcium

Examples Boceprevir, clarithromycin, cobicistat, conivaptan, danoprevir and ritonavir, diltiazem, elvitegravir and ritonavir, grapefruit juice a , idelalisib, indinavir and ritonavir, itraconazole, ketoconazole, lopinavir and ritonavir, nefazodone, nelfinavir, paritaprevir and ritonavir and (ombitasvir and/or dasabuvir), posaconazole, ritonavir, saquinavir and ritonavir, tipranavir and ritonavir, troleandomycin, voriconazole Strong CYP3A Inducers Clinical Impact Coadministration of RYDAPT with strong CYP3A inducers may decrease midostaurin concentrations [see Clinical Pharmacology (12.3)].

Source: FDA drug label - rydapt

7 DRUG INTERACTIONS • Strong cytochrome P450 3A4 inhibitors (e.g., ritonavir, ketoconazole): Use not recommended. The use of strong CYP3A4 inhibitors (e.g., ritonavir, atazanavir, clarithromycin, indinavir, itraconazole, nefazodone, nelfinavir, saquinavir, ketoconazole, telithromycin) with SEREVENT DISKUS is not recommended because increased cardiovascular adverse effects may occur.

Source: FDA drug label - salmeterol xinafoate

Ritonavir and other Potent CYP3A Inhibitors Concomitant use of sildenafil with ritonavir and other potent CYP3A inhibitors is not recommended [ see Clinical Pharmacology (12.3) ]. (7) • Use with ritonavir and other potent CYP3A inhibitors: Not recommended.

Source: FDA drug label - sildenafil

Hepatitis C direct acting antiviral: glecaprevir/pibrentasvir simeprevir ↑ glecaprevir ↑ pibrentasvir ↑ simeprevir It is not recommended to co-administer ritonavir with glecaprevir/pibrentasvir, or simeprevir.

Source: FDA drug label - ritonavir

Examples: Select azole anti-fungals (e.g., itraconazole, ketoconazole, posaconazole, and voriconazole), select macrolide antibiotics (e.g., erythromycin and clarithromycin), select HIV protease inhibitors (e.g., nelfinavir, ritonavir, and darunavir/ritonavir), select HCV protease inhibitors (e.g., boceprevir and telaprevir), cobicistat-containing products, and nefazodone.

Source: FDA drug label - ritonavir

tipranavir/ritonavir ↓ sofosbuvir ↓ velpatasvir Coadministration is not recommended. 7.4 Drugs without Clinically Significant Interactions with VOSEVI Based on drug interaction studies conducted with the components of VOSEVI (sofosbuvir, velpatasvir, and/or voxilaprevir) or VOSEVI, no clinically significant drug interactions have been observed with the following drugs [see Clinical Pharmacology (12.3) ]: VOSEVI: cobicistat, darunavir, elvitegravir, emtricitabine, ethinyl estradiol/norgestimate, gemfibrozil, rilpivirine, ritonavir, tenofovir alafenamide, voriconazole Sofosbuvir/velpatasvir: dolutegravir, ketoconazole, raltegravir Sofosbuvir: methadone, tacrolimus

Source: FDA drug label - sofosbuvir, velpatasvir, and voxilaprevir

ketoconazole, ritonavir) increase tadalafil exposure ( 2.7 , 5.10 , 7.2 ) requiring dose adjustment: Tadalafil tablets for use as needed: no more than 10 mg every 72 hours Tadalafil tablets for once daily use: dose not to exceed 2.5 mg CYP3A4 inducers (e.g. HIV Protease inhibitor — Ritonavir (500 mg or 600 mg twice daily at steady state), an inhibitor of CYP3A4, CYP2C9, CYP2C19, and CYP2D6, increased tadalafil 20-mg single-dose exposure (AUC) by 32% with a 30% reduction in C max , relative to the values for tadalafil 20 mg alone. Ritonavir (200 mg twice daily), increased tadalafil 20-mg single-dose exposure (AUC) by 124% with no change in C max , relative to the values for tadalafil 20 mg alone.

Source: FDA drug label - tadalafil

However, strong inhibitors of CYP3A4 (e.g., ketoconazole, itraconazole, ritonavir) may increase the plasma concentrations of amlodipine to a greater extent.

Source: FDA drug label - telmisartan and amlodipine

7 DRUG INTERACTIONS When co-administering ritonavir with other protease inhibitors (atazanavir, darunavir, fosamprenavir, saquinavir, and tipranavir), see the full prescribing information for that protease inhibitor including important information for drug interactions. HIV-1 Protease Inhibitor: tipranavir ↑ tipranavir See the complete prescribing information for tipranavir for details on co-administration of tipranavir and ritonavir.

Source: FDA drug label - ritonavir

For patients receiving ketoconazole or other potent CYP3A4 inhibitors such as itraconazole, clarithromycin, or ritonavir, the recommended dose of tolterodine tartrate extended-release capsules is 2 mg once daily [see Dosage and Administration (2.2) and Clinical Pharmacology (12.3) ] . For patients receiving ketoconazole or other potent CYP3A4 inhibitors such as itraconazole, miconazole, clarithromycin, ritonavir, the recommended dose of tolterodine tartrate extended-release capsules is 2 mg daily [see Dosage and Administration (2.3) ] .

Source: FDA drug label - tolterodine tartrate

ketoconazole), protease inhibitors (e.g., ritonavir) CYP3A4 Inducers Clinical Impact: The concomitant use of tramadol hydrochloride extended-release tablets and CYP3A4 inducers can decrease the plasma concentration of tramadol [see Clinical Pharmacology (12.3)] , resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence to tramadol, [see Warnings and Precautions (5.7)] .

Source: FDA drug label - tramadol hcl er

ketoconazole), protease inhibitors (e.g., ritonavir) CYP3A4 Inducers Clinical Impact: The concomitant use of tramadol hydrochloride extended-release tablets and CYP3A4 inducers can decrease the plasma concentration of tramadol [see Clinical Pharmacology ( 12.3 )] , resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence to tramadol, [see Warnings and Precautions ( 5.

Source: FDA drug label - tramadol hydrochloride

Examples: Macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), protease inhibitors (e.g., ritonavir) CYP3A4 Inducers Clinical Impact: The concomitant use of tramadol hydrochloride and acetaminophen and CYP3A4 inducers can decrease the plasma concentration of tramadol [see Clinical Pharmacology (12.3) ] , resulting in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence to tramadol.

Source: FDA drug label - tramadol hydrochloride and acetaminophen

The effect of short-term administration of ritonavir (200 mg twice daily, 4 doses) on the pharmacokinetics of a single dose of trazodone (50 mg) has been studied in 10 healthy subjects. Adverse effects including nausea, hypotension, and syncope were observed when ritonavir and trazodone were coadministered.

Source: FDA drug label - trazodone hydrochloride

Systemic/Inhaled/ Nasal/Ophthalmic Corticosteroids: e.g., betamethasone budesonide ciclesonide dexamethasone fluticasone methylprednisolone mometasone prednisone triamcinolone ↑ glucocorticoids Coadministration with corticosteroids whose exposures are significantly increased by strong CYP3A inhibitors can increase the risk for Cushing’s syndrome and adrenal suppression.

Source: FDA drug label - ritonavir

Co-administration of other strong CYP3A4 inhibitors (e.g., ritonavir, atazanavir, clarithromycin, indinavir, itraconazole, nefazodone, nelfinavir, saquinavir, telithromycin, cobicistat-containing products) with Kenalog-40 Injection may cause increased plasma concentration of triamcinolone leading to adverse reactions. ) During postmarketing use, there have been reports of clinically significant drug interactions in patients receiving triamcinolone acetonide and strong CYP3A4 inhibitors (e.g., ritonavir).

Source: FDA drug label - triamcinolone acetonide

diazepam, ethosuximide, lamotrigine, phenytoin) by inhibiting their metabolism or protein binding displacement ( 7.2 ) Patients stabilized on rufinamide should begin valproate therapy at a low dose, and titrate to clinically effective dose ( 7.2 ) Dosage adjustment of amitriptyline/nortriptyline, propofol, warfarin, and zidovudine may be necessary if used concomitantly with valproic acid ( 7.2 ) Topiramate: Hyperammonemia and encephalopathy ( 5.10 , 7.3 ) 7.1 Effects of Co-Administered Drugs on Valproate Clearance Drugs that affect the level of expression of hepatic enzymes, particularly those that elevate levels of glucuronosyltransferases (such as ritonavir), may increase the clearance of valproate.

Source: FDA drug label - valproic acid

[See Dosage and Administration (2.4) and Warnings and Precautions (5.2) .] Ritonavir (600 mg b.i.d.) co-administered with vardenafil hydrochloride tablets 5 mg resulted in a 49-fold increase in vardenafil AUC and a 13­ fold increase in vardenafil C max . The interaction is a consequence of blocking hepatic metabolism of vardenafil by ritonavir, a HIV protease inhibitor and a highly strong CYP3A4 inhibitor, which also inhibits CYP2C9. Ritonavir significantly prolonged the half-life of vardenafil to 26 hours.

Source: FDA drug label - vardenafil hydrochloride

Clinically significant interactions have been reported with inhibitors of CYP3A4 (e.g., erythromycin, ritonavir) causing elevation of plasma levels of verapamil while inducers of CYP3A4 (e.g., rifampin) have caused a lowering of plasma levels of verapamil.

Source: FDA drug label - verapamil hydrochloride

See saquinavir prescribing information for instructions when saquinavir (with or without ritonavir) is co-administered with clarithromycin. Ritonavir (CYP3A inhibitor) Use of VOQUEZNA TRIPLE PAK with ritonavir is not recommended in patients with decreased renal function. See saquinavir prescribing information for instructions when saquinavir (with or without ritonavir) is co-administered with clarithromycin.

Source: FDA drug label - vonoprazan fumarate and amoxicillin

Table 2: Examples of CYP450 Interactions with Warfarin Enzyme Inhibitors Inducers CYP2C9 amiodarone, capecitabine, cotrimoxazole, etravirine, fluconazole, fluvastatin, fluvoxamine, metronidazole, miconazole, oxandrolone, sulfinpyrazone, tigecycline, voriconazole, zafirlukast aprepitant, bosentan, carbamazepine, phenobarbital, rifampin CYP1A2 acyclovir, allopurinol, caffeine, cimetidine, ciprofloxacin, disulfiram, enoxacin, famotidine, fluvoxamine, methoxsalen, mexiletine, norfloxacin, oral contraceptives, phenylpropanolamine, propafenone, propranolol, terbinafine, thiabendazole, ticlopidine, verapamil, zileuton montelukast, moricizine, omeprazole, phenobarbital, phenytoin, cigarette smoking CYP3A4 alprazolam, amiodarone, amlodipine, amprenavir, aprepitant, atorvastatin, atazanavir, bicalutamide, cilostazol, cimetidine, ciprofloxacin, clarithromycin, conivaptan, cyclosporine, darunavir/ritonavir, diltiazem, erythromycin, fluconazole, fluoxetine, fluvoxamine, fosamprenavir, imatinib, indinavir, isoniazid, itraconazole, ketoconazole, lopinavir/ritonavir, nefazodone, nelfinavir, nilotinib, oral contraceptives, posaconazole, ranitidine, ranolazine, ritonavir, saquinavir, telithromycin, tipranavir, voriconazole, zileuton armodafinil, amprenavir, aprepitant, bosentan, carbamazepine, efavirenz, etravirine, modafinil, nafcillin, phenytoin, pioglitazone, prednisone, rifampin, rufinamide 7.3 Drugs that Increase Bleeding Risk Examples of drugs known to increase the risk of bleeding are presented in Table 3 .

Source: FDA drug label - warfarin sodium