Pharmacokinetics of cefetamet pivoxil and interaction with cisapride and N-acetylcysteine.

OBJECTIVE: To evaluate the pharmacokinetics of cefetamet pivoxil and possible interaction with N-acetylcysteine and cisapride in healthy volunteers. METHODS: In a double-blind, randomized three-way crossover study with 12 healthy male volunteers, serum and urine concentrations of cefetamet were determined over 12 h by a validated bioassay method after oral administration of 0.5 g cefetamet pivoxil and, randomly, placebo, 5x20 mg cisapride, or 0.6 g N-acetylcysteine. RESULTS: The study medications were well tolerated, although there were 10 cases of altered bowel movements, two cases of mild, transient headache and one case of increased serum transferase levels (AST and ALT). The mean peak serum level of cefetamet pivoxil in the placebo group was 4.86plus minus1.35 mg/L. The urine recovery/24 h in the placebo group was 41.9plus minus3.8% of the oral dose. The elimination half-life was 3.56plus minus0.92 h. N-Acetylcysteine had no effect on the pharmacokinetics of cefetamet pivoxil. With concomitant administration of cisapride there was an accelerated absorption of cefetamet pivoxil and a slightly increased Cmax of cefetamet. The Cmax values differed significantly (p<0.05) only between the cisapride group (5.76plus minus1.50 mg/L) and the N-acetylcysteine group (4.53plus minus1.18 mg/L). CONCLUSION: None of the small pharmacokinetic differences between the three groups is expected to have any relevance in the treatment of infectious diseases with cefetamet pivoxil.