The effect of ciprofloxacin on antipyrine metabolism

Abstract

The effect of multiple-dose ciprofloxacin on antipyrine metabolism was studied in patients suffering from bacterial infections. The patients were given antipyrine 15 mg/kg intravenously before and after ciprofloxacin treatment. The dosage of ciprofloxacin was 500 mg bd by mouth for 8–10 days. Blood samples were taken at 0, 2, 4, 6, 10 h. Antipyrine total clearance was significantly decreased after ciprofloxacin treatment (0.85±0.45 vs 0.52±0.24 ml/min/kg): elimination rate constants for antipyrine were decreased in all patients after ciprofloxacin, whereas no change in volume of distribution was observed. The average half-life of antipyrine was increased from 9.45±3.34 h to 14.92±3.32 h. In two males with advanced chronic hepatic failure the antipyrine half-lives were extremely prolonged. Our results support the hypothesis that ciprofloxacin inhibits intrinsic hepatic drugmetabolizing capacity and may be a source of clinically important drug interactions, particularly in patients with liver disease.