Overdose of vincristine: experience with a patient.

Vincristine, referred to as a vinka alkaloid, has been used as a component of the various chemotherapeutic regimens. The major side effects of the usual dosage of vincristine are bone marrow suppression, gastrointestinal disorder, and neurotoxicity. A 53-year-old cervical cancer patient received 14 mg (4 mg/m2/day for 2 days) of vincristine instead of vinblastine because of the similarity between the two names. Then life threatening toxicities including paresthesias, bone marrow depression, severe oral mucositis, paralytic ileus, bladder atony, myalgia, muscle weakness, high fever, derangements of various organs (liver, heart), hypertension, and insomnia were encountered. But hypotension and syndrome of inappropriate secretion of antidiuretic hormone (SIADH) were not observed. Other than paresthesias in the extremities, the patient recovered completely from toxic impairments with intensive symptomatic and supportive care. In order to prevent the administration of the overdosed drug, it would be advisable for chemotherapy to be administered only by an experienced physician who is able to check the dose and concentration.