[The effect of phenobarbital on the acetylation of sulfapyridazine and formation of sulfadimethoxine glucronide in man].

In the urine of 20 normal male students-volunteers aged 20 to 30 the percentage of acetylated sulphapyridazine and sulphadimetoxin was measudred 12 hours of taking by them 1.0 g of sulphanilamide. Takinpreliminarily phenobarbital (0.1 g before going to bed for 2 days) did not have any effect on the percentage of acetylated sulphapyridazine in the urine of the examined, nor did it affect the level of the free compound. Phenorbarbital was found to significantly raise the level of sulphadimetoxin from 84.3 up to 88.1 per cent in the urine, the amount of free sulphadimetoxine then declining. In experiments on isolated lenghts of the small intestine of the rat turned inside out it was shown that a coursewise introduction of phenobarbital (25 mg/kg for 5 days) did have any effect on the acetylation of sulphapyridazine.