The metabolism of salicylazosulphapyridine in ulcerative colitis: II The relationship between metabolites and the progress of the disease studied in outpatients.

Serum concentrations of salicylazosulphapyridine (SASP), sulphapyridine (SP), and 5-aminosalicylic acid (5-ASA) were measured in 64 outpatients with ulcerative colitis. About 90% of the patients in remission had serum total SP concentrations above 20 mug/ml. Seven patients, however, had active disease despite a serum total SP concentration > 20 mug/ml. The SASP and the individual SP metabolites did not show any correlation with the disease state. Three g per day seems to be the most effective dose. Plain and enteric-coated tablets produced similar concentrations at equivalent dosage. Side effects due to SASP were frequent in patients who had a total SP concentration > 50 mug/ml of serum.