Amvasc BE Drug Interactions

Cimetidine, antacid (aluminum/magnesium hydroxide), or sildenafil: No significant effect on the pharmacokinetics of amlodipine.
Grapefruit Juice: Coadministration may increase the bioavailability of amlodipine resulting in increased blood pressure lowering effects. Thus, grapefruit should not be taken with amlodipine.
Digoxin: Concomitant use did not change the serum digoxin levels or digoxin renal clearance in normal volunteers.
Ethanol (alcohol): No significant effect on the pharmacokinetics of ethanol.
Warfarin: Concomitant use did not change the warfarin prothrombin response time.
Atorvastatin: No significant change in steady state pharmacokinetic parameters of atorvastatin.
Simvastatin: Concomitant use of multiple doses of amlodipine (10 mg) with higher doses of simvastatin (80 mg) resulted in increased exposure to simvastatin. Do not exceed doses of simvastatin greater than 20 mg daily in patients on amlodipine.
Cytochrome P450 3A4 (CYP3A4) Inhibitors: Concomitant use of amlodipine with strong or moderate CYP3A4 inhibitors [protease inhibitors (e.g., ritonavir), azole antifungals (e.g., ketoconazole, itraconazole), macrolides (e.g., erythromycin, clarithromycin), verapamil or diltiazem] may increase the plasma concentrations of amlodipine to a greater extent. The clinical effects of these pharmacokinetic variations may be more pronounced in the elderly.
Clinical monitoring and dose adjustment may therefore be required.
CYP3A4 Inducers: There is no data available regarding the effect of CYP3A4 inducers on amlodipine. Concomitant use of CYP3A4 inducers (e.g., rifampicin, St. John's Wort) may result in lower plasma concentrations of amlodipine. Amlodipine should be used with caution when administered with CYP3A4 inducers.
Ciclosporin: An increase in trough ciclosporin levels was observed in renal transplant patients when concomitantly administered with amlodipine.
Tacrolimus: Coadministration may increase blood levels of tacrolimus. Monitor blood levels and adjust dosage of tacrolimus as appropriate to avoid toxicity.