Tukon Drug Interactions

Atorvastatin: The risk of myopathy during treatment with other statins is increased with concurrent administration of cyclosporine, fibric acid derivatives (Gemfibrozil, Fenofibrate), lipid-modifying doses of niacin (nicotinic acid), or strong CYP3A4 inhibitors (e.g., clarithromycin, erythromycin, HIV protease inhibitors: ritonavir, lopinavir, and azole antifungals: itraconazole).
Atorvastatin is metabolized by cytochrome P450 3A4. Concomitant administration of atorvastatin with strong inhibitors of CYP3A4 can lead to increases in plasma concentrations of atorvastatin.
Plasma concentration of atorvastatin increase approximately 40% with co-administration of erythromycin, which is a known inhibitor of cytochrome P450 3A4.
Grapefruit juice contains one or more components that inhibit CYP3A4 and can increase plasma concentrations of atorvastatin, especially with excessive grapefruit juice consumption.
Atorvastatin and atorvastatin-metabolites are substrates of the OATP1B1 transporter. Inhibitors of the OATP1B1 (e.g., cyclosporine) can increase the bioavailability of atorvastatin. In cases where coadministration of atorvastatin with cyclosporine is necessary, the dose of atorvastatin should not exceed 10 mg.
Co-administration with antacid reduces plasma concentrations of atorvastatin by approximately 34%.
Plasma concentrations of atorvastatin decrease approximately 26% when co-administered with colestipol.
When multiple doses of atorvastatin and digoxin are coadministered, plasma digoxin concentrations increase by approximately 20%.
Co-administration of atorvastatin and an oral contraceptive increased AUC values for norethindrone and ethinyl estradiol.
Co-administration of atorvastatin with diltiazem resulted in a 51% increase in atorvastatin AUC.
Co-administration with cimetidine reduces plasma concentrations of atorvastatin by approximately 11%.
Concomitant administration of atorvastatin with inducers of cytochrome P450 3A4 (e.g. efavirenz, rifampin) can lead to variable reductions in plasma concentrations of atorvastatin.
Due to the dual interaction mechanism of rifampin, simultaneous co-administration of atorvastatin with rifampin is recommended, as delayed administration of atorvastatin after administration of rifampin has been associated with a significant reduction in atorvastatin plasma concentrations.
Co-administration with antipyrine reduces plasma concentrations of antipyrine by approximately 11%.
Co-administration of amlodipine with atorvastatin resulted in increase in AUC and decrease in Cmax.
Amlodipine: Strong inhibitors of CYP3A4 (e.g., ketoconazole, itraconazole, ritonavir) may increase the plasma concentrations of amlodipine to a greater extent. Symptoms of hypotension and edema should be monitored when amlodipine is co-administered with CYP3A4 inhibitors.
Blood pressure should be closely monitored when amlodipine is co-administered with CYP3A4 inducers.