The relapse-preventing effect of methyl-salazosulphapyridine compared to salazosulphapyridine during long-term treatment of ulcerative colitis. A double-blind controlled trial.

In an attempt to improve the relapse-preventing effect of salazosulphapyridine (SASP) and to encircle the part of the molecule essential for therapeutic actin, methyl-SASP was compared to SASP in a controlled double-blind trial without cross-over. The patient group comprised 33 patients with ulcerative colitis who had been symptom-free for 1--6 months on continuous treatment with SASP (on an average 2 g daily). The daily doses were SASP 1 g X 3 and methyl-SASP 125 mg x 3. Thirty patients completed the trial, 14 on SASP and 16 on methyl-SASP. Applying clinical criteria, the relapse rate after 6 months was 0.14 in the SASP group and 0.69 in the methyl-SASP group. The difference is highly significant. The blood concentrations of SASP, methyl-SASP, sulphapyridine (SP), and methyl-sulphapyridine (methyl-SP) were measured after 3 and 6 months. The methyl-SASP concentration was on an average twice as high as that of SASP, and the methyl-SP on an average 1/10 of SP (the differences are significant). It is concluded that whereas SASP showed a relapse-preventing effect in ulcerative colitis in this study comparable to that previously reported, the effect of methyl-SASP was only comparable to that of placebo, and the active substance in SASP does not seem to be unsplit SASP.