Sulphasalazine and 5-aminosalicylic acid in long-term treatment of ulcerative colitis: report on tolerance and side-effects

Abstract Background. Use of sulphasalazine in ulcerative colitis patients is hampered by a variety of side-effects, including male infertility. 5-aminosalicylic acid is better tolerated and has been increasingly used to treat patients intolerant/allergic to sulphasalazine but it may also be associated with side-effects. Aim. To evaluate tolerance of long-term treatment with sulphasalazine and 5-aminosalicylic acid in ulcerative colitis. Methods. Side-effects to sulphasalazine (2–3 g/day) and 5-aminosalicylic acid (1.2–2.4 g/day) were recorded in 685 patients: 410 patients received only sulphasalazine, 130 only 5-aminosalicylic acid, and 145 both drugs. In patients with side-effects to sulphasalazine, a desensitisation protocol (rechallenge) was attempted to improve tolerance, and patients still presenting side-effects after desensitisation were switched to 5-aminosalicylic acid. Male fertility was also assessed in 42 males on sulphasalazine and on 5-aminosalicylic acid. Results. Side-effects were observed in 110 555 patients (20%) on sulphasalazine and in 18 275 patients (6.5%) on 5-aminosalicylic acid during a median period of follow-up of 7 and 5 years, respectively. Desensitisation was achieved in 40% of patients intolerant to sulphasalazine. 5-aminosalicylic acid intake induced side-effects in 2 130 patients (1.5%) who had not taken sulphasalazine before versus 4 91 patients (4%) tolerating sulphasalazine and 12 54 patients (22%) intolerant/allergic to sulphasalazine, the difference in incidence of side-effects in the two latter groups being statistically significant (4.4% vs 20.8%, p=0.001). Fertility was found to be affected in all patients on sulphasalazine but improved when put onto 5-aminosalicylic acid. Conclusions. 5-aminosalicylic acid should be considered the drug of choice in the treatment of ulcerative colitis bearing in mind that intolerance or allergy may occur in a few patients also on this drug.