Pharmacokinetics of Alfentanil in Patients Treated with Either Cimetidine or Ranitidine

    loading  Checking for direct PDF access through Ovid



The pharmacokinetics of alfentanil were studied after single dose intravenous administration of 125 μg/kg to 19 intensive care unit patients who were divided into 3 groups. Group I was given oral antacid, and groups II and III were given, respectively, cimetidine 1200 mg/day IV and ranitidine 300 mg/day IV for 48 hours before administration of alfentanil. Alfentanil plasma concentrations were determined over the 8 hours following drug administration using a radio-immunoassay. Pharmacokinetic parameters were calculated using a noncompartmental analysis. In group II, alfentanil plasma concentrations were significantly higher than in the other groups. In addition, significant changes involving the elimination half-life (142.3 ± 35 vs 81.14 ± 11 and 88.1 ± 33 minutes), total clearance (1.27 ± 0.5 vs 3.56 ± 1.17 and 2.74 ± 1 ml/kg/min) and total volume of distribution related to the pseudo distribution phase (226 ± 73 vs 336 ± 76 and 271 ± 61 ml/kg) were found in group II vs groups I and III. These results suggest that pretreatment with cimetidine alters alfentanil pharmacokinetics after single dose administration. In contrast, ranitidine does not appear to have a significant effect.

Related Topics

    loading  Loading Related Articles