GI symptoms, anorexia, wt loss, weakness, hyperpigmentation, amenorrhoea, cataracts, cough or hoarseness, impaired fertility and gonadal function, dry skin, liver damage, gynaecomastia.
Potentially Fatal: Bone marrow depression manifesting as thrombocytopaenia, leucopaenia, anaemia. Interstitial pulmonary fibrosis (known as "busulfan lung" on prolonged treatment).