Oral ethanol ingestion altered nifedipine pharmacokinetics in the rat: a preliminary study

We examined the pharmacokinetics of intravenously administered nifedipine in the presence or absence of concomitant alcohol ingestion in the rat. In the presence of alcohol, the area under the nifedipine plasma concentration vs. time curve and half-life of drug elimination were increased, and the rate constant of elimination was significantly decreased (p less than 0.05), while the apparent volume of distribution was apparently unaffected. Clearance, normalized to control, was significantly decreased (p less than 0.01). Since nifedipine and ethanol both undergo dehydrogenation in their metabolism, it is possible that this observed drug-drug interaction may be due to a metabolic interference. It is not known at this time whether such an interaction exists in man.