Dose-dependent changes in sulfamethazine kinetics in rapid and slow isoniazid acetylators.
The pharmacokinetics of sulfamethazine (SMZ) was studied in 44 healthy volunteers. After an oral dose of 10 mg/kg we found the usual distribution of rapid and slow acetylators. The differences in the t1/2s between the phenotypes were not due to variations in renal clearance. Repeat studies at this dose showed very little intraindividual variation in t1/2s. After a 40 mg/kg dose there was an increase in the t1/2 of SMZ in every subject. The implications of these results on methods of phenotyping are discussed.
D000107:Acetylation; D000328:Adult; D004305:Dose-Response Relationship, Drug; D005260:Female; D006207:Half-Life; D006801:Humans; D007538:Isoniazid / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D013418:Sulfamethazine / Q000008:administration & dosage / Q000378:metabolism*
D013418:Sulfamethazine; D007538:Isoniazid