Dose Conversion from Diltiazem to Amlodipine

Key Pharmacologic Differences

Diltiazem is a nondihydropyridine that affects both cardiac tissue and vascular smooth muscle, causing negative chronotropic and inotropic effects, whereas Amlodipine is a dihydropyridine with greater selectivity for peripheral vascular smooth muscle, producing primarily vasodilation without significant cardiac effects 1, 2

When switching from diltiazem to amlodipine, initiate amlodipine at standard starting doses regardless of the diltiazem dose, with the American Heart Association recommending starting doses of 2.5-5 mg once daily for adults and 0.1-0.3 mg/kg/day for pediatrics 1, 3
The European Society of Cardiology recommends uptitrating amlodipine gradually from the starting dose to achieve blood pressure control, with a maximum adult dose of 10 mg once daily 1, 4

Heart rate monitoring is critical when switching between these agents, as diltiazem causes bradycardia through AV node suppression, while amlodipine may cause reflex tachycardia due to peripheral vasodilation, according to the American College of Cardiology 1, 3

The American Heart Association recommends discontinuing diltiazem and starting amlodipine 5 mg once daily, with titration by 2.5-5 mg increments if blood pressure remains uncontrolled 1, 4