Summary
Background: Tioguanine (TG) is an antimetabolite which may be regarded as an alternative to azathioprine (AZA)/mercaptopurine (MP) in patients with inflammatory bowel diseases.
Aims : To evaluate the tolerance and efficacy of TG in patients with Crohn's disease, intolerant or resistant to AZA/MP.
Methods : An open prospective study was made on Crohn's disease patients treated with TG. Intolerance to AZA/MP was defined as a reaction occurring within 1 month after introduction of AZA/MP, including pancreatitis, abdominal pain, fever, arthralgia, myalgia, cutaneous rash, fatigue, alopecia, hepatitis and digestive intolerance. Resistance to AZA/MP was defined as the persistence of activity after at least 3 months of AZA/MP therapy.
Results : Forty‐nine Crohn's disease patients (36 women, 13 men; intolerance: n = 39; resistance: n= 10) were treated with TG (20 mg/day). Clinical pancreatitis did not recur under TG. Five patients (10%) had to stop TG due to intolerant reactions observed 13–21 days after TG was started. No haematological side‐effects were observed under TG. The probability of clinical remission without corticosteroids or infliximab at 6 and 12 months was 46% and 79%, respectively, in the 40 patients with active disease at baseline. The probability of clinical relapse during maintenance TG therapy at 6 and 12 months was 29% and 53%, respectively, in the 28 patients in remission at baseline or who had achieved remission on TG.
Conclusions : TG is a possible alternative treatment in Crohn's disease patients, intolerant (especially for pancreatitis) or resistant to AZA/MP.