Monitoring azathioprine therapy

Before starting azathioprine therapy, thiopurine methyltransferase (TPMT) testing helps predict the risk of adverse events in a patient. TPMT testing does not identify all patients at risk of severe toxicity, so close monitoring of full blood count and liver biochemistry during therapy is still essential.

The role of thiopurine metabolite monitoring in autoimmune hepatitis is not well established; however, it can guide dosing and be used to check adherence.