Azathioprine

Azathioprine is metabolised to the active compound mercaptopurine, a purine analogue that inhibits purine synthesis. A thiopurine methyltransferase (TPMT) test may be needed to look for individuals prone to azathioprine toxicity.

Adverse effects include

• bone marrow depression
• nausea/vomiting
• pancreatitis

A significant interaction may occur with allopurinol and hence lower doses of azathioprine should be used.