to test the effect of trimethoprim ( an antibiotic commonly administered with sulfamethoxazole ) on the disposition of the antiarrhythmic procainamide hydrochloride and its active metabolite n-acetylprocainamide , 10 healthy men received 1 g of procainamide hydrochloride orally on two occasions , coadministered with placebo or trimethoprim ( 100 mg twice a day for 2 days before and then 200 mg with the procainamide dose ) .
C0003195
antiarrhythmic
C0600311
procainamide hydrochloride