Nifedipine: kinetics and dynamics after single oral doses.

Serum nifedipine concentrations and hemodynamic changes were evaluated in ten healthy volunteers after a single 40-mg oral dose of nifedipine. Peak serum concentrations averaged 45 micrograms/l, attained 2.7 h after dosage. The mean elimination half-life was 5.9 h (range: 3-12 h). Blood pressure, ventricular rate, and echocardiographically-determined rate of circumferential fiber shortening did not differ between placebo and nifedipine trials. Five additional subjects ingested nifedipine once in the control state and on a second occasion with a standard breakfast. Coingestion of food delayed the peak serum nifedipine concentration but did not alter the area under the serum concentration curve. Thus the pharmacokinetic profile of nifedipine indicates that a three- or four-times-daily dose is, in general, appropriate in clinical practice. Completeness of absorption is not altered by coadministration with food. Adverse hemodynamic effects of single oral doses in healthy persons are not evident.