Vincristine overdose: experience with 3 patients.

Vincristine overdose (7.5 mg/m2) was accidentally administered to 3 children with acute lymphoblastic leukemia. Treatment included double-volume exchange transfusion, phenobarbital administered prophylactically, and folinic acid rescue 18 mg every 3 hours for 16 doses. Vincristine levels were also assayed and showed a dramatic decline in postexchange levels in the 2 patients who survived and an almost unchanged value in the patient who succumbed. Early signs of toxicity in the 2 survivors were peripheral neuropathy (day 4), bone marrow toxicity (day 5), gastrointestinal toxicity (days 6 and 7), and hypertension (days 7 and 8). Marrow aplasia lasted for 4 and 10 days, peripheral neuropathy for 15 and 42 days, gastrointestinal toxicity for 3 and 5 days, and hypertension for 5 and 14 days. The 2 children were discharged on days 13 and 16 and cytostatic therapy was restarted on days 18 and 25. Both are alive without evidence of leukemia. The third patient developed liver and marrow toxicity on day 3 and died on day 9. Postmortem examination showed leukemia infiltration of the liver and spleen.