Concentrations of trimethoprim-sulfamethoxazole in blood after a single, large oral dose

Concentrations of trimethoprim (TMP) and sulfamethoxazole (SMZ) in blood were determined in seven healthy volunteers after ingestion of 720 mg of TMP and 3,600 mg of SMZ (nine tablets of TMP-SMZ, 1:5 ratio) as a single oral dose. The mean levels of drug in blood achieved during the first 8 h after drug administration ranged from 6.12 to 8.32 mug/ml for TMP and 98 to 120 mug/ml for SMZ. These concentrations easily exceeded the previously reported minimal inhibitory concentrations for clinical isolates of Neisseria gonorrhoeae. The combination of TMP-SMZ given as a single, large oral dose may be a useful therapeutic regimen for patients with uncomplicated gonorrhea and susceptible microorganisms.