Avamax Drug Interactions

Cytochrome P450 3A4 (CYP3A4) Inhibitors (e.g., ciclosporin, erythromycin, clarithromycin, HIV protease inhibitors, azole antifungals, etc): These drugs increase plasma atorvastatin concentrations; the risk of myopathy is increased with coadministration of atorvastatin with CYP3A4 inhibitors.
Clarithromycin: Coadministration of atorvastatin 80 mg once a day for 8 days with clarithromycin 500 mg twice a day for 9 days resulted in a 4.4-fold increase in atorvastatin AUC. In cases where coadministration of clarithromycin with atorvastatin is necessary, the maintenance dose of atorvastatin should not exceed 20 mg per day.
Erythromycin: Coadministration of atorvastatin 80 mg once a day with erythromycin 500 mg four times a day increased plasma atorvastatin concentrations (approximately 33%).
Azithromycin: Coadministration of atorvastatin 10 mg once a day with azithromycin 500 mg once a day did not change plasma atorvastatin concentrations.
Protease Inhibitors: Coadministration of atorvastatin with several combinations of HIV protease inhibitors, as well as the HCV protease inhibitor telaprevir, significantly increased atorvastatin AUC compared to that of atorvastatin alone. Avoid concomitant use of atorvastatin in patients taking HIV protease inhibitor tipranavir plus ritonavir, or the HCV protease inhibitor telaprevir. Exercise caution when prescribing atorvastatin and use the lowest dose necessary in patients taking the HIV protease inhibitor lopinavir plus ritonavir. Exercise caution and atorvastatin dose should not exceed 20 mg in patients taking the HIV protease inhibitors saquinavir plus ritonavir, darunavir plus ritonavir, fosamprenavir, or fosamprenavir plus ritonavir. Close clinical monitoring is recommended and atorvastatin dose should not exceed 40 mg in patents taking the HIV protease inhibitor nelfinavir or the HCV protease inhibitor boceprevir.
Itraconazole: Coadministration of atorvastatin 40 mg single dose with itraconazole 200 mg once a day for 4 days resulted in a 3.3-fold increase in atorvastatin AUC. Exercise caution when atorvastatin dose exceeds 20 mg in patients taking itraconazole.
Amiodarone, Verapamil: These drugs increase exposure to atorvastatin; monitor lipid levels to ensure that the lowest dose of atorvastatin is used.
Diltiazem: Coadministration of atorvastatin 40 mg single dose with diltiazem 240 mg once a day for 28 days resulted in a 51% increase in atorvastatin AUC.
Cimetidine: Coadministration did not change atorvastatin plasma concentrations and LDL-C reduction.
Ezetimibe: The use of ezetimibe alone is associated with myopathy. The risk of myopathy may be increased with concomitant use of ezetimibe and atorvastatin. Appropriate clinical monitoring of these patients is recommended.
Gemfibrozil: Avoid coadministration of atorvastatin with gemfibrozil due to increased risk of myopathy/rhabdomyolysis when HMG-CoA reductase inhibitors are coadministered with gemfibrozil.
Other Fibrates: Because it is known that the risk of myopathy during treatment with HMG-CoA reductase inhibitors is increased with coadministration of other fibrates, atorvastatin should be used with caution when used concomitantly with other fibrates.
Niacin: The risk of skeletal muscle effects may be enhanced when atorvastatin is used in combination with niacin; consider reducing atorvastatin dosage.
Grapefruit Juice: Contains one or more components that inhibit CYP3A4 and can increase plasma atorvastatin concentrations, especially with excessive grapefruit juice consumption (over 1.2 L per day). Thus, concomitant intake of grapefruit juice and atorvastatin is not recommended.
Ciclosporin: Atorvastatin and atorvastatin-metabolites are substrates of organic anion transporting polypeptide 1B1 (OATP1B1), e.g., ciclosporin. Coadministration of atorvastatin 10 mg once a day with ciclosporin 5.2 mg/kg/day significantly increased atorvastatin AUC. The coadministration of atorvastatin with ciclosporin should be avoided.
CYP3A4 Inducers: Administration of atorvastatin with CYP3A4 inducers (e.g., efavirenz, rifampicin, St. John's wort) may result in decreased plasma atorvastatin concentrations. Due to rifampicin's dual interaction mechanism (i.e., CYP3A4 induction and inhibition of hepatocyte uptake transporter OATP1B1), simultaneous coadministration of atorvastatin with rifampicin is recommended since significant decreases in plasma atorvastatin concentrations have been observed after the delayed administration of atorvastatin following rifampicin administration.
Antacids: Coadministration with an oral antacid (containing magnesium and aluminum) decreased plasma atorvastatin concentrations (approximately 35%). There was no change in LDL-C reduction.
Colestipol: Coadministration with colestipol decreased plasma atorvastatin concentrations by about 25%. However, a greater LDL-C reduction was seen after coadministration of atorvastatin with colestipol than when either drug was given alone.
Digoxin: Steady state plasma digoxin concentrations increased by about 20% when multiple doses of atorvastatin and digoxin were coadministered. Patients taking digoxin should be monitored appropriately.
Oral Contraceptives: Coadministration with an oral contraceptive containing norethisterone and ethinyl estradiol increased AUC values for norethisterone and ethinyl estradiol by about 30% and 20%, respectively. These increased concentrations should be considered when selecting oral contraceptive doses.
Colchicine: Cases of myopathy, including rhabdomyolysis, have been reported with atorvastatin coadministered with colchicine. Exercise caution when prescribing atorvastatin with colchicine.
Amlodipine: Coadministration of atorvastatin 80 mg with amlodipine 10 mg increased atorvastatin AUC by 18%.
Warfarin: Atorvastatin had no clinically significant effect on prothrombin time when administered to patients receiving chronic warfarin treatment.
Fusidic acid: The risk of myopathy including rhabdomyolysis may be increased by coadministration of systemic fusidic acid with statins. Coadministration of this combination may cause increased plasma concentrations of both agents. The mechanism of this interaction is still unknown. Although interaction studies with atorvastatin and fusidic acid have not been conducted, there have been reports of rhabdomyolysis (including some fatalities) in patients receiving this combination. If treatment with fusidic acid is necessary, statin treatment should be discontinued throughout the duration of the fusidic acid treatment. (See Table 5.)

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