Table I.
Dosing Information for Calcium Channel Blockers Currently Marketed in the United States
| Drug | Proprietary Name | Indications Approved | Form; Strength; Dose | Time to Peak Effect (h) | Elimination Half‐Life (h) | Comments |
|---|---|---|---|---|---|---|
| Amlodipine | Norvasc (Pfizer Inc., New York, NY) | Hypertension; chronic, stable, and vasospastic angina | Tablet; 2.5, 5, 10 mg; once daily | 6–12 | 30–50 | No effect of grapefruit juice on pharmacokinetics; available in fixed‐dose combinations with benazepril (Lotrel; Novartis Pharmaceutical Corporation, East Hanover, NJ) or atorvastatin (Caduet; Pfizer Inc., New York, NY). |
| Bepridil | Vascor (Ortho‐McNeil Pharmaceutical, Inc., Raritan, NJ) | Refractory angina | Tablet; 200, 300, 400 mg; once daily | 2–3 | 26–64 | Can cause torsade de pointes‐type ventricular tachycardia. Does not lower blood pressure. |
| Diltiazem | Tiazac (Forest Laboratories Inc., New York, NY); Cardizem CD, LA (Biovail Pharmaceuticals, Inc., Morrisville, NC); Cartia XT (Andrx Laboratories, Hackensack, NJ) Dilacor XR (Watson Laboratories, Inc., Corona, CA) | Hypertension; chronic, stable, and vasospastic angina; atrial fibrillation or flutter; paroxysmal supraventricular tachycardia | Immediate‐release (IR), controlled release (CR) and IV forms; 180–540 mg; once daily | 0.5–1.5 (IR); 6–11 (SR) | 2–5 (IR); 2.5 (SR) | Contraindicated in patients with sick‐sinus syndrome and 2nd or 3rd degree atrioventricular block. Cardizem LA can be given at bedtime. Known inhibitor of CYP3A4; as such it slows metabolism of drugs such as simvastatin, cyclosporine, and erythromycin. |
| Felodipine | Plendil (AstraZeneca Pharmaceuticals LP, Wilmington, DE) | Hypertension | CR;2.5, 5, 10 mg; once daily | 2.5–5 | 11–16 | Grapefruit juice causes a two‐fold or more increase in felodipine bioavailability; grapefruit juice effect may last 24–72 hours; available as a fixed‐dose combination with enalapril (Lexxel; AstraZeneca Pharmaceuticals LP, Wilmington, DE). |
| Isradipine | Dynacirc CR (Reliant Pharmaceuticals, Liberty Corner, NJ) | Hypertension | Tablet; 2.5, 5 mg; once daily | 1.5 | 8–12 | Edema rate is low compared with other calcium channel blockers. |
| Nicardipine | Cardene (Roche Pharmaceuticals, Nutley, NJ) | Hypertension, angina | IR tablet; 20, 30 mg; three times daily | 0.5–2.0 | 8 | Available in an IV form for hypertension treatment. As effective as nitroprusside for hypertensive emergencies. |
| Nifedipine | Adalat (Bayer Pharmaceuticals, Pittsburgh, PA); Procardia XL (Pfizer Inc., New York, NY) | Hypertension, angina | Dose varies based on indication; CR capsule; 30, 60, 90 mg; once daily | 0.5 | 2 | IR capsules are no longer used for the control of essential hypertension or for the acute reduction of blood pressure. |
| Nimodipine | Nimotop (Bayer Pharmaceuticals, Pittsburgh, PA) | Subarachnoid hemorrhage | Gelatin capsule; 60 mg; every 4 hours for 21 days | 1 | 1–2 | Crosses the blood‐brain barrier readily; oral therapy should commence within 96 hours of the subarachnoid hemorrhage. |
| Nisoldipine | Sular (First Horizon Pharmaceutical Corporation, Alpharetta, GA) | Hypertension | SR tablet; 10,20, 30, 40 mg; once daily | 6–12 | 7–12 | Grapefruit juice significantly increases nisoldipine bioavailability. |
| Verapamil | Calan, Calan SR (GD Searle LLC, New York, NY); Covera HS (GD Searle LLC, New York, NY); Verelan PM (Elan Biopharmaceuticals, San Diego, CA) | Hypertension; angina atrial fibrillation or flutter; paroxysmal supraventricular tachycardia | IR tablet: dose varies based on indication; SR products: 120–360 mg; once daily | 0.5–1.0 (IR); 4–6 (SR) | 4.5–12 (IR); 4.5–12 (CR) | Nocturnally indicated forms of verapamil available with early morning peak action. |
| CYP3A4=cytochrome P450 3A4 | ||||||