69 interactions on record
Fluconazole No Dose Adjustment Fluconazole: [see Pharmacokinetics ( 12.3 )] Anti-Gout Agents: Colchicine (in patients with renal or hepatic impairment) Contraindicated Colchicine: Colchicine is a substrate for both CYP3A and the efflux transporter, P-glycoprotein (Pgp).
Source: FDA drug label - clarithromycin
Telaprevir Decrease AUC by 92% Systemic Hormonal Contraceptives Prevention or Management: Advise patients to change to non-hormonal methods of birth control during rifampin therapy Estrogens Decrease exposure Progestins Anticonvulsants Phenytoin Administered with rifampin 450 mg daily Decrease exposure Antiarrhythmics Disopyramide Decrease exposure Mexiletine Decrease exposure Quinidine Decrease exposure Propafenone Decrease AUC by 50%–67% Tocainide Decrease exposure Antiestrogens Tamoxifen Decrease AUC by 86% Toremifene Decrease steady state concentrations of toremifene in serum Antithrombotic Agents Clopidogrel Prevention or Management: Concomitant use of clopidogrel and rifampin should be discouraged Increase active metabolite exposure and risk of bleeding Ticagrelor Prevention or Management: Avoid use Decrease exposure Antipsychotics Haloperidol Decrease plasma concentrations by 70% Lurasidone Prevention or Management : Concomitant use is contraindicated (See CONTRAINDICATIONS ) Decrease exposure Oral Anticoagulants Prevention or Management: Perform prothrombin time daily or as frequently as necessary to establish and maintain the required dose of anticoagulant Warfarin Decrease exposure Antifungals Fluconazole Decrease AUC by 23% Itraconazole Prevention or Management: Not recommended 2 weeks before and during itraconazole treatment Decrease exposure Ketoconazole Decrease exposure Caspofungin Prevention or Management: Refer to the caspofungin prescribing information for caspofungin dose adjustment.
Source: FDA drug label - rifampin
(See PRECAUTIONS .) Abrocitinib: When co-administered with fluconazole (inhibitor of CYP2C9, 2C19, and 3A4), the systemic exposure (AUC) of abrocitinib was approximately 4.8-fold higher and the combined exposure (AUC) of abrocitinib and its active metabolites was approximately 2.5-fold higher compared to when abrocitinib was administered alone (See PRECAUTIONS ). Clinically or potentially significant drug interactions between fluconazole and the following agents/classes have been observed and are described in greater detail below: Abrocitinib : Drug interaction studies indicate that when co-administered with fluconazole (strong inhibitor of CYP2C19; moderate inhibitor of CYP2C9 and CYP3A4), the systemic exposure of abrocitinib and its active metabolites increased (See CLINICAL PHARMACOLOGY ). Avoid concomitant use of abrocitinib with fluconazole.
Source: FDA drug label - fluconazole
( 2.4 , 7.1 ) • Fluconazole : Avoid concomitant use; reduce LORBRENA dose if concomitant use cannot be avoided. Fluconazole Avoid concomitant use of LORBRENA with fluconazole. Concomitant use of LORBRENA with fluconazole may increase lorlatinib plasma concentrations [see Clinical Pharmacology (12.3) ] , which may increase the incidence and severity of adverse reactions of LORBRENA.
Source: FDA drug label - lorlatinib
Mild or Moderate CYP3A Inhibitors: Clotrimazole, antibiotics (e.g., erythromycin, fluconazole), calcium channel blockers (e.g., verapamil, diltiazem, nifedipine, nicardipine), amiodarone, danazol, ethinyl estradiol, cimetidine, lansoprazole and omeprazole May increase tacrolimus whole blood trough concentrations and increase the risk of serious adverse reactions (e.g., neurotoxicity, QT prolongation) [see Warnings and Precautions ( 5.6 , 5.11 , 5.12 )] Monitor tacrolimus whole blood trough concentrations and reduce tacrolimus dose if needed [see Dosage and Administration ( 2.2 , 2.6 ) and Clinical Pharmacology (12.3) ] .
Source: FDA drug label - tacrolimus
Dosage adjustment of clobazam oral suspension may be necessary when co-administered with strong CYP2C19 inhibitors (e.g., fluconazole, fluvoxamine, ticlopidine) or moderate CYP2C19 inhibitors (e.g., omeprazole) [see Clinical Pharmacology ( 12.3 )].
Source: FDA drug label - clobazam
Therefore, give one third the recommended dosage of deflazacort when moderate or strong CYP3A4 inhibitors (e.g., clarithromycin, fluconazole, diltiazem, verapamil, grapefruit juice) are used concomitantly with deflazacort [see Dosage and Administration (2.5) and Clinical Pharmacology (12.3) ] .
Source: FDA drug label - deflazacort
Concomitant administration of moderate or strong CYP3A4 inhibitors such as azole antifungals (e.g., ketoconazole, itraconazole, voriconazole, fluconazole), verapamil, macrolides (e.g., clarithromycin, erythromycin), diltiazem, and grapefruit juice can increase the plasma concentrations of the estrogen or the progestin or both.
Source: FDA drug label - drospirenone and ethinyl estradiol
[See Clinical Pharmacology (12.3).] Substances Increasing the Systemic Exposure of COCs (enzyme inhibitors): Concomitant administration of moderate or strong CYP3A4 inhibitors like azole antifungals (for example, ketoconazole, itraconazole, voriconazole, fluconazole), verapamil, macrolides (for example, clarithromycin, erythromycin), diltiazem, and grapefruit increase the serum concentrations of both estradiol and dienogest.
Source: FDA drug label - estradiol valerate and estradiol valerate/dienogest
Concomitant administration of strong or moderate CYP3A4 inhibitors such as itraconazole, voriconazole, fluconazole, grapefruit juice, or ketoconazole may increase plasma estrogen and/or progestin concentrations.
Source: FDA drug label - etonogestrel and ethinyl estradiol vaginal ring
Antifungals : fluconazole voriconazole ↑ etravirine ↔ fluconazole voriconazole Co-administration of etravirine and fluconazole significantly increased etravirine exposures. The amount of safety data at these increased etravirine exposures is limited, therefore, etravirine and fluconazole should be co-administered with caution. No dose adjustment of etravirine tablets or fluconazole is needed.
Source: FDA drug label - etravirine
Table 14: Clinically Important Drug Interactions: Effect of other Drugs on Guanfacine Extended-Release Tablets Concomitant Drug Name or Drug Class Clinical Rationale and Magnitude of Drug Interaction Clinical Recommendation Strong and moderate CYP3A4 inhibitors, e.g., ketoconazole, fluconazole Guanfacine is primarily metabolized by CYP3A4 and its plasma concentrations can be significantly affected resulting in an increase in exposure Consider dose reduction [see Dosage and administration (2.7) ] Strong and moderate CYP3A4 inducers, e.g., rifampin, efavirenz Guanfacine is primarily metabolized by CYP3A4 and its plasma concentrations can be significantly affected resulting in a decrease in exposure Consider dose increase [see Dosage and administration (2.7) ] Strong and moderate CYP3A4 inhibitors increase guanfacine exposure.
Source: FDA drug label - guanfacine
Ibrutinib : Moderate inhibitors of CYP3A4 such as fluconazole may increase plasma ibrutinib concentrations and increase risk of adverse reactions associated with ibrutinib. If ibrutinib and fluconazole are concomitantly administered, reduce the dose of ibrutinib as instructed in ibrutinib prescribing information and the patient should be frequently monitored for any adverse reactions associated with ibrutinib.
Source: FDA drug label - fluconazole
7 DRUG INTERACTIONS Potential for other drugs to affect ivacaftor CYP3A inhibitors: Reduce KALYDECO dosage in patients aged 6 months and older when co-administered with strong CYP3A inhibitors (e.g., ketoconazole) or moderate CYP3A inhibitors (e.g., fluconazole). Co-administration with fluconazole, a moderate inhibitor of CYP3A, increased ivacaftor exposure by 3-fold. Therefore, a reduction of the KALYDECO dosage is recommended for patients aged 6 months and older taking concomitant moderate CYP3A inhibitors, such as fluconazole and erythromycin.
Source: FDA drug label - ivacaftor
Substances increasing the systemic concentrations of HCs: Co-administration of certain HCs and strong or moderate CYP3A4 inhibitors such as itraconazole, voriconazole, fluconazole, grapefruit juice, or ketoconazole may increase the systemic concentrations of progestins, including norethindrone.
Source: FDA drug label - norethindrone
( 7.1 ) Fluconazole (strong CYP2C9 inhibitor): Increases systemic exposure of ramelteon; administer with caution. Fluconazole (strong CYP2C9 inhibitor) The AUC 0-inf and C max of ramelteon was increased by approximately 150% when ramelteon was coadministered with fluconazole. Ramelteon should be administered with caution in subjects taking strong CYP2C9 inhibitors such as fluconazole [see Clinical Pharmacology (12.5) ] .
Source: FDA drug label - ramelteon
Moderate CYP3A Inhibitors Limit the dose of ranolazine to 500 mg twice daily in patients on moderate CYP3A inhibitors, including diltiazem, verapamil, erythromycin, fluconazole, and grapefruit juice or grapefruit-containing products [see Dosage and Administration (2.2) , Clinical Pharmacology (12.3) ].
Source: FDA drug label - ranolazine
Calcium channel blockers : Certain calcium channel antagonists (nifedipine, isradipine, amlodipine, verapamil, and felodipine) are metabolized by CYP3A4.
Source: FDA drug label - fluconazole
Azoles (e.g., ketoconazole, miconazole, clotrimazole, fluconazole, etc.) In vitro and in vivo animal studies of the combination of amphotericin B and imidazoles suggest that imidazoles may induce fungal resistance to amphotericin B.
Source: FDA drug label - amphotericin b
(See CLINICAL PHARMACOLOGY: Drug Interaction Studies .) Saquinavir : Fluconazole increases the AUC of saquinavir by approximately 50%, C max by approximately 55%, and decreases the clearance of saquinavir by approximately 50% due to inhibition of saquinavir’s hepatic metabolism by CYP3A4 and inhibition of P-glycoprotein. Dosage adjustment of saquinavir may be necessary.
Source: FDA drug label - fluconazole
7.4 Drugs with No Observed Interactions with REYATAZ No clinically significant drug interactions were observed when REYATAZ was coadministered with methadone, fluconazole, acetaminophen, atenolol, or the nucleoside reverse transcriptase inhibitors lamivudine or zidovudine [see Clinical Pharmacology, Tables 21 and 22 (12.3) ] .
Source: FDA drug label - atazanavir
HMG-CoA reductase inhibitors : The risk of myopathy and rhabdomyolysis increases when fluconazole is coadministered with HMG-CoA reductase inhibitors metabolized through CYP3A4, such as atorvastatin and simvastatin, or through CYP2C9, such as fluvastatin.
Source: FDA drug label - fluconazole
) Azithromycin: An open-label, randomized, three-way crossover study in 18 healthy subjects assessed the effect of a single 800 mg oral dose of fluconazole on the pharmacokinetics of a single 1200 mg oral dose of azithromycin as well as the effects of azithromycin on the pharmacokinetics of fluconazole. There was no significant pharmacokinetic interaction between fluconazole and azithromycin. Azithromycin : An open-label, randomized, three-way crossover study in 18 healthy subjects assessed the effect of a single 1200 mg oral dose of azithromycin on the pharmacokinetics of a single 800 mg oral dose of fluconazole as well as the effects of fluconazole on the pharmacokinetics of azithromycin.
Source: FDA drug label - fluconazole
Fluconazole (200 mg) has been used with busulfan.
Source: FDA drug label - busulfan
Drugs that have been shown, or would be expected, to increase plasma carbamazepine levels include aprepitant, cimetidine, ciprofloxacin, danazol, diltiazem, macrolides (e.g., erythromycin, clarithromycin), fluoxetine, fluvoxamine, trazodone, omeprazole, oxybutynin, isoniazid, niacinamide (nicotinamide), azoles (e.g., ketaconazole, itraconazole, fluconazole, voriconazole), acetazolamide, verapamil, ticlopidine, grapefruit juice, and protease inhibitors.
Source: FDA drug label - carbamazepine
The concomitant administration of amiodarone or other CYP2C9 inhibitors such as fluconazole with carvedilol may enhance the β-blocking activity, resulting in further slowing of the heart rate or cardiac conduction.
Source: FDA drug label - carvedilol
Coadministration of celecoxib with drugs that are known to inhibit CYP2C9 (e.g., fluconazole) may enhance the exposure and toxicity of celecoxib whereas co-administration with CYP2C9 inducers (e.g., rifampin) may lead to compromised efficacy of celecoxib.
Source: FDA drug label - celecoxib
Although clinical studies have not been performed, based on the involvement of the cytochrome P-450 3A family in clonazepam metabolism, inhibitors of this enzyme system, notably oral antifungal agents (e.g., fluconazole), should be used cautiously in patients receiving clonazepam because they may impair the metabolism of clonazepam leading to exaggerated concentrations and effects.
Source: FDA drug label - clonazepam
7.4 Drug-Drug Interaction Studies Four pharmacokinetic studies evaluated the effects of co-administration of voriconazole (200 mg BID), fluconazole (200 mg QD), cimetidine (800 mg BID), and propafenone (225 mg BID) on systemic levels of colchicine.
Source: FDA drug label - colchicine
) Cyclophosphamide : Combination therapy with cyclophosphamide and fluconazole results in an increase in serum bilirubin and serum creatinine.
Source: FDA drug label - fluconazole
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
7.5 Drugs Without Clinically Significant Interactions with Efavirenz No dosage adjustment is recommended when efavirenz is given with the following: aluminum/magnesium hydroxide antacids, azithromycin, cetirizine, famotidine, fluconazole, lorazepam, nelfinavir, nucleoside reverse transcriptase inhibitors (abacavir, emtricitabine, lamivudine, stavudine, tenofovir disoproxil fumarate, zidovudine), paroxetine, and raltegravir.
Source: FDA drug label - efavirenz
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. Table 2: Drugs Affected by Phenytoin Interacting Agent Examples Drugs whose efficacy is impaired by phenytoin Azoles Fluconazole, ketoconazole, itraconazole, posaconazole, voriconazole Antineoplastic agents Irinotecan, paclitaxel, teniposide Delavirdine Phenytoin can substantially reduce the concentrations of delavirdine.
Source: FDA drug label - extended phenytoin sodium
Calcium channel blockers : Certain calcium channel antagonists (nifedipine, isradipine, amlodipine, verapamil, and felodipine) are metabolized by CYP3A4.
Source: FDA drug label - fluconazole
HMG-CoA reductase inhibitors : The risk of myopathy and rhabdomyolysis increases when fluconazole is coadministered with HMG-CoA reductase inhibitors metabolized through CYP3A4, such as atorvastatin and simvastatin, or through CYP2C9, such as fluvastatin.
Source: FDA drug label - fluconazole
The following are examples of medications that may increase the glucose-lowering effect of sulfonylureas including glimepiride, increasing the susceptibility to and/or intensity of hypoglycemia: oral anti-diabetic medications, pramlintide acetate, insulin, angiotensin converting enzyme (ACE) inhibitors, H 2 receptor antagonists, fibrates, propoxyphene, pentoxifylline, somatostatin analogs, anabolic steroids and androgens, cyclophosphamide, phenyramidol, guanethidine, fluconazole, sulfinpyrazone, tetracyclines, clarithromycin, disopyramide, quinolones, and those drugs that are highly protein-bound, such as fluoxetine, nonsteroidal anti-inflammatory drugs, salicylates, sulfonamides, chloramphenicol, coumarins, probenecid and monoamine oxidase inhibitors. 7.3 Cytochrome P450 2C9 Interactions There may be an interaction between glimepiride and inhibitors (e.g., fluconazole) and inducers (e.g., rifampin) of cytochrome P450 2C9. Fluconazole may inhibit the metabolism of glimepiride, causing increased plasma concentrations of glimepiride which may lead to hypoglycemia.
Source: FDA drug label - glimepiride
The effect of concomitant administration of DIFLUCAN ® (fluconazole) and glipizide has been demonstrated in a placebo-controlled crossover study in normal volunteers. The mean percentage increase in the glipizide AUC after fluconazole administration was 56.9% (range: 35 to 81).
Source: FDA drug label - glipizide
The effect of concomitant administration of fluconazole and glipizide has been demonstrated in a placebo-controlled crossover study in normal volunteers. All subjects received glipizide alone and following treatment with 100 mg of fluconazole as a single oral daily dose for 7 days, the mean percent increase in the glipizide AUC after fluconazole administration was 56.9% (range: 35% to 81%).
Source: FDA drug label - glipizide and metformin hydrochloride
Hydrochlorothiazide: Concomitant oral administration of 100 mg fluconazole and 50 mg hydrochlorothiazide for 10 days in 13 normal volunteers resulted in a significant increase in fluconazole AUC and C max compared to fluconazole given alone. Hydrochlorothiazide : In a pharmacokinetic interaction study, coadministration of multiple-dose hydrochlorothiazide to healthy volunteers receiving fluconazole increased plasma concentrations of fluconazole by 40%.
Source: FDA drug label - fluconazole
Calcium channel blockers : Certain calcium channel antagonists (nifedipine, isradipine, amlodipine, verapamil, and felodipine) are metabolized by CYP3A4.
Source: FDA drug label - fluconazole
CYP3A4 inhibitors such as itraconazole, voriconazole, fluconazole, grapefruit juice, or ketoconazole may increase systemic exposure of estrogen and/or progestin component of COCs.
Source: FDA drug label - levonorgestrel and ethinyl estradiol
Based on known metabolic profiles, clinically significant drug interactions are not expected between lopinavir and ritonavir and dapsone, trimethoprim/sulfamethoxazole, azithromycin, erythromycin, or fluconazole.
Source: FDA drug label - lopinavir and ritonavir
Losartan : Fluconazole inhibits the metabolism of losartan to its active metabolite (E-31 74) which is responsible for most of the angiotensin II-receptor antagonism which occurs during treatment with losartan.
Source: FDA drug label - fluconazole
Fluconazole, an inhibitor of cytochrome P450 2C9, decreased the AUC of the active metabolite by approximately 40%, but increased the AUC of losartan by approximately 70% following multiple doses. Fluconazole, an inhibitor of P450 2C9, decreased active metabolite concentration and increased losartan concentration.
Source: FDA drug label - losartan potassium and hydrochlorothiazide
Examples: Diltiazem, atazanavir, erythromycin, fluconazole, verapamil Strong CYP3A4 Inducers Clinical Impact: Concomitant use of lurasidone hydrochloride with strong CYP3A4 inducers decreased the exposure of lurasidone compared to the use of lurasidone hydrochloride alone [see Clinical Pharmacology ( 12.3 )].
Source: FDA drug label - lurasidone 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 Hydrochloride Injection and CYP3A4, CYP2B6, CYP2C19, or CYP2C9 inducers can decrease the plasma concentration of methadone (see CLINICAL PHARMACOLOGY ), resulting in decreased efficacy or onset of withdrawal symptoms in patients physically dependent on methadone.
Source: FDA drug label - methadone hydrochloride
Less potent inhibitors include saquinavir, nefazodone, fluconazole, grapefruit juice, fluoxetine, fluvoxamine, zileuton, and clotrimazole.
Source: FDA drug label - methylergonovine maleate
(See PRECAUTIONS .) Midazolam: The effect of fluconazole on the pharmacokinetics and pharmacodynamics of midazolam was examined in a randomized, cross-over study in 12 volunteers. In addition, a 7.5 mg dose of midazolam was orally ingested on the first day, 0.05 mg/kg was administered intravenously on the fourth day, and 7.5 mg orally on the sixth day. Fluconazole reduced the clearance of IV midazolam by 51%.
Source: FDA drug label - fluconazole
Drugs such as diltiazem, erythromycin, fluconazole, itraconazole, ketoconazole, saquinavir, and verapamil were shown to significantly increase the C max and AUC of orally administered midazolam.
Source: FDA drug label - midazolam hydrochloride
Table 2: Clinically Significant Drug Interactions with Nateglinide Drugs That May Increase the Blood-Glucose-Lowering Effect of Nateglinide and Susceptibility to Hypoglycemia Drugs: Nonsteroidal anti-inflammatory drugs (NSAIDs), salicylates, monoamine oxidase inhibitors, non-selective beta-adrenergic-blocking agents, anabolic hormones (e.g., methandrostenolone), guanethidine, gymnema sylvestre, glucomannan, thioctic acid, and inhibitors of CYP2C9 (e.g., amiodarone, fluconazole, voriconazole, sulfinpyrazone) or in patients known to be poor metabolizers of CYP2C9 substrates, alcohol.
Source: FDA drug label - nateglinide
Calcium channel blockers : Certain calcium channel antagonists (nifedipine, isradipine, amlodipine, verapamil, and felodipine) are metabolized by CYP3A4.
Source: FDA drug label - fluconazole
CYP3A4 inhibitors such as itraconazole, voriconazole, fluconazole, grapefruit juice, or ketoconazole may increase plasma hormone concentrations.
Source: FDA drug label - norelgestromin and ethinyl estradiol
CYP3A4 inhibitors such as itraconazole, voriconazole, fluconazole, grapefruit juice, or ketoconazole may increase plasma hormone concentrations.
Source: FDA drug label - norethindrone acetate and ethinyl estradiol
CYP3A4 inhibitors such as itraconazole, voriconazole, fluconazole, grapefruit juice, or ketoconazole may increase plasma hormone concentrations.
Source: FDA drug label - norethindrone and ethinyl estradiol
CYP3A4 inhibitors such as itraconazole, voriconazole, fluconazole, grapefruit juice, or ketoconazole may increase plasma hormone concentrations.
Source: FDA drug label - norgestimate and ethinyl estradiol
Table 2: 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 Antacids Antacids may affect absorption of phenytoin. Table 3: Drugs Affected by Phenytoin Interacting Agent Examples Drugs whose efficacy is impaired by phenytoin Azoles Fluconazole, ketoconazole, itraconazole, posaconazole, voriconazole Antineoplastic agents Irinotecan, paclitaxel, teniposide Delavirdine Phenytoin can substantially reduce the concentrations of delavirdine.
Source: FDA drug label - phenytoin
Substrates or Inhibitors of CYP2C19 Blood levels and/or toxicity of propranolol may be increased by co-administration with substrates or inhibitors of CYP2C19, such as fluconazole, cimetidine, fluoxetine, fluvoxamine, teniposide, and tolbutamide. Substrates or Inhibitors of CYP2C19 Blood levels and/or toxicity of propranolol may be increased by co-administration with substrates or inhibitors of CYP2C19, such as fluconazole, cimetidine, fluoxetine, fluvoxamine, teniposide, and tolbutamide.
Source: FDA drug label - propranolol hydrochloride
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
Azole Antifungal Agents: fluconazole itraconazole ketoconazole This interaction study has been performed with a dose higher than the recommended dose for EDURANT assessing the maximal effect on the coadministered drug.
Source: FDA drug label - rilpivirine hydrochloride
HMG-CoA reductase inhibitors : The risk of myopathy and rhabdomyolysis increases when fluconazole is coadministered with HMG-CoA reductase inhibitors metabolized through CYP3A4, such as atorvastatin and simvastatin, or through CYP2C9, such as fluvastatin.
Source: FDA drug label - fluconazole
Drug interactions have also been noted with cimetidine, fluconazole, cyclosporine, rifampin, and caffeine. The influence of terbinafine on the pharmacokinetics of fluconazole, cotrimoxazole (trimethoprim and sulfamethoxazole), zidovudine or theophylline was not considered to be clinically significant. Coadministration of a single dose of fluconazole (100 mg) with a single dose of terbinafine resulted in a 52% and 69% increase in terbinafine C max and AUC, respectively.
Source: FDA drug label - terbinafine
Drug interactions have also been noted with cimetidine, fluconazole, cyclosporine, rifampin, and caffeine. The influence of terbinafine on the pharmacokinetics of fluconazole, cotrimoxazole (trimethoprim and sulfamethoxazole), zidovudine or theophylline was not considered to be clinically significant. Coadministration of a single dose of fluconazole (100 mg) with a single dose of terbinafine resulted in a 52% and 69% increase in terbinafine C max and AUC, respectively.
Source: FDA drug label - terbinafine hydrochloride
Agents for Opportunistic Infections Antifungals: Fluconazole Itraconazole Ketoconazole ↑ Tipranavir, ↔ Fluconazole Fluconazole increases tipranavir concentrations but dose adjustments are not needed. Fluconazole doses >200 mg/day are not recommended.
Source: FDA drug label - tipranavir
) Tofacitinib: Coadministration of fluconazole (400 mg on Day 1 and 200 mg once daily for 6 days [Days 2 to 7]) and tofacitinib (30 mg single dose on Day 5) in healthy subjects resulted in increased mean tofacitinib AUC and C max values of approximately 79% (90% CI: 64% to 96%) and 27% (90% CI: 12% to 44%), respectively, compared to administration of tofacitinib alone. (See CLINICAL PHARMACOLOGY: Drug Interaction Studies .) Tofacitinib: Systemic exposure to tofacitinib is increased when tofacitinib is coadministered with fluconazole. Reduce the dose of tofacitinib when given concomitantly with fluconazole (i.e., from 5 mg twice daily to 5 mg once daily as instructed in the XELJANZ ® [tofacitinib] label).
Source: FDA drug label - fluconazole
(See CONTRAINDICATIONS and PRECAUTIONS .) Oral hypoglycemics: The effects of fluconazole on the pharmacokinetics of the sulfonylurea oral hypoglycemic agents tolbutamide, glipizide, and glyburide were evaluated in three placebo-controlled studies in normal volunteers. (See PRECAUTIONS .) Tolbutamide: In 13 normal male volunteers, there was significant increase in tolbutamide (500 mg single dose) AUC and C max following the administration of fluconazole. There was a mean ± SD increase in tolbutamide AUC of 26% ± 9% (range: 12 to 39%).
Source: FDA drug label - fluconazole
Concomitant use of CYP2C9 inhibitors (e.g., amiodarone, fluconazole, miconazole, oxandrolone) can decrease torsemide clearance and increase torsemide plasma concentrations.
Source: FDA drug label - torsemide
Triazolam: Fluconazole increases the AUC of triazolam (single dose) by approximately 50%, C max by 20% to 32%, and increases t ½ by 25% to 50% due to the inhibition of metabolism of triazolam. Dosage adjustments of triazolam may be necessary.
Source: FDA drug label - fluconazole
Voriconazole : Voriconazole is a substrate for both CYP2C9 and CYP3A4 isoenzymes. Concurrent administration of oral Voriconazole (400 mg Q12h for 1 day, then 200 mg Q12h for 2.5 days) and oral fluconazole (400 mg on Day 1, then 200 mg Q24h for 4 days) to 6 healthy male subjects resulted in an increase in C max and AUC τ of voriconazole by an average of 57% (90% CI: 20% to 107%) and 79% (90% CI: 40% to 128%), respectively. In a follow-on clinical study involving 8 healthy male subjects, reduced dosing and/or frequency of voriconazole and fluconazole did not eliminate or diminish this effect.
Source: FDA drug label - fluconazole
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