Somnolence, hypotension, and metabolic acidosis following high-dose teniposide treatment in children with leukemia.

This report describes an unexpected adverse effect in three children receiving teniposide at 3-5 times the conventional dosage (i.e. 200 mg/m2) plus cytarabine as part of continuation therapy for acute lymphocytic leukemia. Pharmacokinetic studies in each patient had demonstrated high teniposide clearances, and thus the increased dosage requirements were necessary to attain plasma concentrations similar to those expected for patients with average drug clearance. At 3-4 h after the beginning of the 4-h simultaneous infusions of teniposide and cytarabine, these patients experienced somnolence, hypotension, and metabolic acidosis. The adverse events were associated with elevated teniposide plasma concentrations during the infusions compared with those in patients receiving similar doses without toxicity, and clinically significant ethanol concentrations, presumably from the teniposide formulation. Blood concentrations of cremophor and histamine, which are also constituents of the teniposide formulation, were not measured. In addition, concomitant therapy with antiemetic agents in patients who may have been mildly volume-depleted due to emesis may also play a contributory role. Prolonging the infusion time for patients receiving teniposide doses above 500 mg/m2 will avoid excessive teniposide and ethanol plasma concentrations and minimize the risk of this potentially serious side effect.