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Mibefradil, a pharmacologically distinct calcium antagonist
1Division of Clinical and Administrative Pharmacy, College of Pharmacy, University of Iowa, Iowa City 52242, USA.
Pharmacotherapy
|June 10, 1998
Summary
Mibefradil, a novel calcium channel blocker, effectively treats hypertension and angina by dilating blood vessels without negative inotropic effects. It offers convenient once-daily dosing but requires caution due to potential drug interactions.
Area of Science:
- Pharmacology
- Cardiovascular Medicine
Background:
- Mibefradil represents a new class of calcium antagonists distinct from traditional agents.
- It selectively targets T-type voltage-gated plasma membrane calcium channels in vascular smooth muscle.
Purpose of the Study:
- To evaluate the efficacy and safety of mibefradil in treating hypertension and chronic stable angina.
- To characterize its pharmacokinetic and pharmacodynamic properties.
Main Methods:
- Clinical studies involving patients with hypertension and angina.
- Dose-response assessments for blood pressure and exercise tolerance.
- Ambulatory electrocardiograph (ECG) monitoring for ischemic events.
- In vitro studies on cytochrome P450 inhibition.
Main Results:
- Mibefradil demonstrated dose-related reductions in blood pressure for hypertension.
- Significant improvements in exercise duration and reduced angina symptoms were observed in angina patients.
- High oral bioavailability, long half-life, and favorable trough:peak ratios support once-daily dosing.
- Common adverse events included dizziness and headache; frequent ECG changes were first-degree atrioventricular block and sinus bradycardia.
Conclusions:
- Mibefradil is an effective antihypertensive and antianginal agent with a favorable hemodynamic profile.
- Its unique mechanism and pharmacokinetic properties allow for convenient dosing.
- Contraindications exist due to significant drug interactions mediated by cytochrome P450 inhibition.