Acute diarrhea during azathioprine treatment of type I autoimmune hepatitis.

Sporadic descriptions of acute onset of watery diarrhea within a few hours to a few weeks azathioprine administration beginning have been reported, particularly in inflammatory bowel disease patients. This article reports the case of a woman treated with azathioprine because of type I autoimmune hepatitis, who developed acute watery diarrhea after more than two months of therapy. In two occasions the patient reassumed the drug and in a few hours diarrhea recurred. Subsequent 6-mercaptopurine treatment was well tolerated, suggesting that the previous side-effect could be due to the nitroimidazole moiety of azathioprine.