Effects of calcium channel inhibitors on ethanol effects and pharmacokinetics in healthy volunteers.

Previous studies have shown that calcium channel antagonists alter the effects of alcohol in animals and humans. We selected a phenylalkylamine, verapamil, and a dihydropyridine, nimodipine, to determine whether these drugs would affect the subjective or psychomotor effects of ethanol in humans. Subjects ingested verapamil (80 mg, PO), nimodipine (30 and 60 mg, PO), or placebo 60 min before drinking an alcohol (0.7 g/kg) or placebo beverage. Subjects' mood, psychomotor performance, physiological status, and blood alcohol levels were assessed up to 3 h after beverage ingestion. Alcohol increased "drunk" ratings and impaired psychomotor performance (p < 0.05). Blood alcohol levels were decreased by nimodipine pretreatment, but not by verapamil pretreatment. Subjective and psychomotor effects of alcohol were not altered as a function of nimodipine or verapamil pretreatment. Nimodipine, verapamil, and alcohol, either alone or in combination, had no effect on blood pressure or heart rate.