[Pharmacokinetics of nifedipine and its metabolite after a single oral dose of the drug in patients with stenocardia of effort].

The pharmacokinetics of nifedipine and its primary metabolite 2,6-dimethyl-4-(2-nitrophenyl)-3,5-pyridine carboxylate was studied in 7 patients with angina of effort after a single oral administration of nifedipine ("Corinfar" tablets) in doses of 20 and 30 mg. The binding of nifedipine and its metabolite to blood serum proteins was determined. Nifedipine appeared in the blood serum of the patients 1.5-2 hrs after the drug intake, the maximal serum concentration was observed 1.13 hrs after the intake. The mean half-life period of nifedipine in the serum was 4.51 hrs. With an increase of the nifedipine dose, its pharmacokinetics underwent linear changes. Nifedipine and its metabolite were not detected in the urine. Binding to the blood serum proteins was 97.4% for nifedipine and 90.5% for its metabolite. 20 mg of nifedipine is suggested to be insufficient for the creation of the effective drug concentration in the blood.