Pharmacokinetics of isradipine in patients with chronic liver disease.

The pharmacokinetics of the dihydropyridine calcium antagonist isradipine has been examined in 8 healthy volunteers, 7 patients with non-cirrhotic chronic liver disease (CLD), and 8 patients with biopsy-proven cirrhosis (CIR). Isradipine was simultaneously given orally (12C 5 mg) and i.v. (13C 1 mg). Systemic availability was significantly increased from 17% to 16% in controls and CLD, respectively, to 37% in CIR. The corresponding systemic clearances averaged 1.1, 0.9 and 0.6 l.min-1, the reduction in cirrhotics being significant. Both aminopyrine demethylation capacity, a measure of hepatic microsomal function, and indocyanine green disappearance, a measure of hepatic perfusion, were correlated with the reduction in systemic clearance, and the reduction in oral clearance was correlated with the reciprocal of the serum bile acid concentration. The loss of first-pass extraction should be considered when this calcium antagonist is given perorally in patients with hepatic cirrhosis.