Pharmacokinetics of metioprim in normal subjects and patients with impaired renal function

The pharmacokinetics of metioprim, a new competitive inhibitor of bacterial dihydrofolate reductases, were studied after a single oral dose of 100 mg in two young healthy subjects, four elderly volunteers, and eight patients with impaired renal function. The pharmacokinetic parameters of unchanged metioprim were derived by analyzing plasma level curves using a two-compartment model. Plasma half-lives determined for the beta phase were 10.5 to 11.5 h in young volunteers, 12.0 to 12.9 h in elderly subjects, and 13.2 to 15.3 h in patients with renal impairment. A significant correlation between the overall elimination rate constant and the creatinine clearance was demonstrated.