This is an analogue of the naturally occurring purine, guanine, and is an anti-neoplastic with actions and uses similar to those of mercaptopurine.

Indications: induction of remission and maintenance in acute myeloid leukaemia; acute lymphoblastic leukaemia; chronic myeloid leukaemia.

Cautions: reduce dose in renal failure.

Contra-indications: Pregnancy; breast-feeding.

Side effect: As for mercaptopurine (gastrointestinal side effects are less frequent than mercaptopurine)

Dose: induction 100 - 200mg/m2 by mouth in 1 – 2 divided doses for 5 – 20 days; maintenance, usually 60 – 200mg/m2 daily.