Use of 6-Mercaptopurine in Autoimmune Hepatitis Patients Intolerant to Azathioprine

Approximately 10% of patients with autoimmune hepatitis (AIH) do not respond to treatment with azathioprine (AZA) or are intolerant of it. Although effective second-line agents exist (e.g., mycophenolate mofetil), some require drug-level monitoring, are expensive, or have significant adverse effects. Although AZA is a prodrug of 6-mercaptopurine (6-MP), AZA intolerance does not necessarily lead to 6-MP intolerance.

Researchers retrospectively investigated response and tolerance to 6-MP in 22 patients (18 women; median age, 53 years) with AIH who had inadequate response or developed AZA intolerance and were switched to 6-MP. AZA was replaced with 6-MP starting at a dose of 25 mg/day and increased to ≥50 mg/day or more if tolerated. Complete t…