Cocaine abuse may influence the response to imatinib in CML patients.

Cocaine is a 2-beta-carbomethoxy-3beta-benzoxytropane, which effects local anesthetic action by blocking the initiation or conduction of nerve impulse 1. Many drugs of abuse are substrates (amphetamines, codeine, nicotine) or inhibitors (cocaine) of polymorphic cytochrome p450 enzyme, which is the same metabolic pathway of imatinib mesylate É, the presently standard drug for Ph+ chronic myeloid leukemia (CML). We describe here two patients with Ph+ CML, who during imatinib treatment practiced cocaine abuse, which concomitantly increased several side effects while response to imatinib was reduced.