Letermovir

pitavastatin, simvastatin ↑ HMG-CoA reductase inhibitors Co-administration of PREVYMIS and pitavastatin or simvastatin is not recommended. When PREVYMIS is co-administered with cyclosporine, use of either pitavastatin or simvastatin is contraindicated due to significantly increased pitavastatin or simvastatin concentrations and risk of myopathy or rhabdomyolysis [see Contraindications (4) ] .

pitavastatin, simvastatin ↑ HMG-CoA reductase inhibitors Co-administration of PREVYMIS and pitavastatin or simvastatin is not recommended. When PREVYMIS is co-administered with cyclosporine, use of either pitavastatin or simvastatin is contraindicated due to significantly increased pitavastatin or simvastatin concentrations and risk of myopathy or rhabdomyolysis [see Contraindications (4) ] .

Table 6: Effect of Other Drugs on Voriconazole Pharmacokinetics [see Clinical Pharmacology (12.3) ] Drug/Drug Class (Mechanism of Interaction by the Drug) Voriconazole Plasma Exposure (C max and AUC τ after 200 mg every 12 hours) Recommendations for Voriconazole Dosage Adjustment/Comments Rifampin and Rifabutin (CYP450 Induction) Significantly Reduced Contraindicated Efavirenz (400 mg every 24 hours) (CYP450 Induction) Significantly Reduced Contraindicated High-dose Ritonavir (400 mg every 12 hours) (CYP450 Induction) Significantly Reduced Contraindicated Low-dose Ritonavir (100 mg every 12 hours) (CYP450 Induction) Reduced Coadministration 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 Carbamazepine (CYP450 Induction) Not Studied In Vivo or In Vitro , but Likely to Result in Significant Reduction Contraindicated Long Acting Barbiturates (e.g., phenobarbital, mephobarbital) (CYP450 Induction) Not Studied In Vivo or In Vitro , but Likely to Result in Significant Reduction Contraindicated Phenytoin (CYP450 Induction) Significantly Reduced Increase voriconazole maintenance dose from 4 mg/kg to 5 mg/kg IV every12 hours Letermovir (CYP2C9/2C19 Induction) Reduced If concomitant administration of voriconazole with letermovir cannot be avoided, monitor for reduced effectiveness of voriconazole.

No drug interaction studies have been conducted with amlodipine besylate and atorvastatin calcium and other drugs, although studies have been conducted in the individual amlodipine and atorvastatin components, as described below: Amlodipine Increased Risk of Myopathy and Rhabdomyolysis ( 2 , 5.1 , 7.3 , 12.3 ) Cyclosporine, tipranavir plus ritonavir, glecaprevir plus pibrentasvir Avoid atorvastatin Clarithromycin, itraconazole, saquinavir plus ritonavir, darunavir plus ritonavir, fosamprenavir, fosamprenavir plus ritonavir, elbasvir plus grazoprevir,letermovir Do not exceed 20 mg atorvastatin daily Nelfinavir Do not exceed 40 mg atorvastatin daily Lopinavir plus ritonavir, simeprevir, fibric acid derivatives, erythromycin, azole antifungals, lipid-modifying doses of niacin, colchicine Consider the risk/benefit of concomitant use with atorvastatin Other Lipid-Lowering Medications: Increased risk of myopathy (7) . In patients taking saquinavir plus ritonavir, darunavir plus ritonavir, fosamprenavir,fosamprenavir plus ritonavir, elbasvir plus grazoprevir or letermovir, do not exceed atorvastatin 20 mg. Examples: Tipranavir plus ritonavir, glecaprevir plus pibrentasvir, lopinavir plus ritonavir, simeprevir, saquinavir plus ritonavir, darunavir plus ritonavir, fosamprenavir, fosamprenavir plus ritonavir, elbasvir plus grazoprevir, letermovir, nelfinavir, and ledipasvir plus sofosbuvir.

Significantly increases atorvastatin plasma levels. Do not exceed ATORVALIQ 20 mg.

7 DRUG INTERACTIONS Drug Interactions that may Increase the Risk of Myopathy and Rhabdomyolysis with atorvastatin ( 2.6 , 5.1 , 7.1 , 12.3 ) Interacting Agents Prescribing Recommendations Cyclosporine, tipranavir plus ritonavir, glecaprevir plus pibrentasvir Avoid atorvastatin Clarithromycin, itraconazole, saquinavir plus ritonavir, darunavir plus ritonavir, fosamprenavir, fosamprenavir plus ritonavir, elbasvir plus grazoprevir, letermovir Do not exceed 20 mg atorvastatin daily Nelfinavir Do not exceed 40 mg atorvastatin daily Lopinavir plus ritonavir, simeprevir, fibric acid derivatives, erythromycin, azole antifungals, lipid-modifying doses of niacin, colchicine Consider the risk/benefit of concomitant use with atorvastatin • Other Lipid-Lowering Medications: Use with fibrate products or lipid-modifying doses (≥1 g/day) of niacin increases the risk of adverse skeletal muscle effects. • In patients taking saquinavir plus ritonavir, darunavir plus ritonavir, fosamprenavir, fosamprenavir plus ritonavir, elbasvir plus grazoprevir or letermovir, do not exceed atorvastatin 20 mg. Examples: Tipranavir plus ritonavir, glecaprevir plus pibrentasvir, lopinavir plus ritonavir, simeprevir, saquinavir plus ritonavir, darunavir plus ritonavir, fosamprenavir, fosamprenavir plus ritonavir, elbasvir plus grazoprevir, letermovir, nelfinavir, and ledipasvir plus sofosbuvir.

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 )].

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).

Co-administration requires dosage adjustment of letermovir to 240 mg once daily in adults and pediatric patients ≥12 years; dose adjustment may be needed in younger patients.

7.2 Potential for PREVYMIS to Affect Other Drugs Co-administration of PREVYMIS with midazolam results in increased midazolam plasma concentrations, indicating that letermovir is a moderate inhibitor of CYP3A [see Clinical Pharmacology (12.3) ] . CYP3A Substrates Examples: alfentanil, fentanyl, midazolam, and quinidine ↑ CYP3A substrate When PREVYMIS is co-administered with a CYP3A substrate, refer to the prescribing information for dosing of the CYP3A substrate with a moderate CYP3A inhibitor .

Weak/moderate CYP3A4/P-gp inhibitor that may increase sirolimus concentrations. Monitor and adjust dosage as needed.

7.4 Drugs without Clinically Significant Interactions with PREVYMIS No clinically significant interactions were observed in adult clinical drug-drug interaction studies of letermovir and acyclovir, digoxin, mycophenolate mofetil, fluconazole, itraconazole, posaconazole, ethinyl estradiol, and levonorgestrel.

HMG-CoA Reductase Inhibitors atorvastatin ↑ atorvastatin When PREVYMIS is co-administered with atorvastatin, do not exceed an atorvastatin dosage of 20 mg daily . When PREVYMIS is co-administered with cyclosporine, use of atorvastatin is not recommended.

7.4 Drugs without Clinically Significant Interactions with PREVYMIS No clinically significant interactions were observed in adult clinical drug-drug interaction studies of letermovir and acyclovir, digoxin, mycophenolate mofetil, fluconazole, itraconazole, posaconazole, ethinyl estradiol, and levonorgestrel.

fluvastatin, lovastatin, pravastatin, rosuvastatin ↑ HMG-CoA reductase inhibitors When PREVYMIS is co-administered with these statins, a statin dosage reduction may be necessary .

7.4 Drugs without Clinically Significant Interactions with PREVYMIS No clinically significant interactions were observed in adult clinical drug-drug interaction studies of letermovir and acyclovir, digoxin, mycophenolate mofetil, fluconazole, itraconazole, posaconazole, ethinyl estradiol, and levonorgestrel.

fluvastatin, lovastatin, pravastatin, rosuvastatin ↑ HMG-CoA reductase inhibitors When PREVYMIS is co-administered with these statins, a statin dosage reduction may be necessary . When PREVYMIS is co-administered with cyclosporine, use of lovastatin is not recommended.

Antibiotics nafcillin ↓ letermovir Co-administration of PREVYMIS and nafcillin is not recommended due to potential for loss of efficacy of PREVYMIS.

Proton Pump Inhibitors omeprazole ↓ omeprazole Clinical monitoring and dose adjustment may be needed.

pantoprazole ↓ pantoprazole Clinical monitoring and dose adjustment may be needed.

7.4 Drugs without Clinically Significant Interactions with PREVYMIS No clinically significant interactions were observed in adult clinical drug-drug interaction studies of letermovir and acyclovir, digoxin, mycophenolate mofetil, fluconazole, itraconazole, posaconazole, ethinyl estradiol, and levonorgestrel.

fluvastatin, lovastatin, pravastatin, rosuvastatin ↑ HMG-CoA reductase inhibitors When PREVYMIS is co-administered with these statins, a statin dosage reduction may be necessary .

fluvastatin, lovastatin, pravastatin, rosuvastatin ↑ HMG-CoA reductase inhibitors When PREVYMIS is co-administered with these statins, a statin dosage reduction may be necessary .