[Nifedipine pharmacokinetics in liver cirrhosis patients after the administration of a single oral dose].

Abstract

The niphedipine pharmacokinetics was investigated in the patients with hepatic cirrhosis, in comparison with a group of healthy subjects, after administering unique doses of 10 mg per os. The niphedipine concentrations in serum were determined by a gas chromatography method. The niphedipine pharmacokinetics may be described in correspondence with the open pharmacokinetic model. The values of pharmacokinetic parameters of niphedipine in the patients with hepatic cirrhosis are significantly modified in comparison with those noticed in the healthy subjects. An increase in the level of the maximum concentrations (158 ng/ml versus 68 ng/ml), of the biological half time (11.9 hours versus 2.5 hours) and of the area under the curve of the drug concentrations in time (450 ng.ml-1.hour versus 205 ng.ml-1.hour) were found. The relative bioavailability [correction of biodisponibility] of niphedipine was double in the patients with hepatic cirrhosis versus the healthy subjects. The modified pharmacokinetics of niphedipine in the patients with hepatic cirrhosis and the great individual variations found, require a decrease of the dose in this category of patients and a surveillance of the clinical effect.