Mesalazine tolerance in patients with inflammatory bowel disease and previous intolerance or allergy to sulphasalazine or sulphonamides.

Fifty patients intolerant of or allergic to sulphasalazine (SASP) or sulphonamides were treated with mesalazine. Eighty per cent of patients continued treatment during the time of follow-up (mean, 8.4 months); 14% (7 of 50 patients) had to stop the treatment with mesalazine because of side effects. The patients with allergic reactions, including rash, fever, and systemic manifestations from SASP, were most likely to be intolerant of or allergic to mesalazine (four of seven patients); two of them developed a similar reaction from both SASP and mesalazine. Two patients (2 of 12) with previous haematologic side effects had to discontinue mesalazine treatment, one because of mild neutropaenia and one because of an elevation of liver enzyme values. One patient experienced gastrointestinal side effects from both mesalazine and SASP. Altogether, 4 (4 of 50) patients experienced gastrointestinal symptoms from mesalazine. Two of them had had a flare-up of the symptoms of the colitis when treated with SASP. All side effects were rapidly reversible after withdrawal of the drug. Patients with severe allergic reactions with systemic manifestations from SASP should be treated with caution with 5-aminosalicylic acid preparations.