Objective: To document ondansetron-induced dystonia, hypoglycemia, and seizures in a child.
Case summary: A 4-year-old boy was admitted with dystonia following an intravenous dose of ondansetron 2 mg (0.13 mg/kg) that he had received for vomiting that day. In the emergency department, he developed generalized tonicclonic seizures lasting for a few minutes. He was administered lorazepam 1.5 mg (0.1 mg/kg) to control the seizures. His blood glucose level was 10 mg/dL; the hypoglycemia responded promptly to intravenous dextrose 10% (7 mL/kg). Serum electrolytes, renal profile, capillary blood gas, and results of a computed tomography scan of the brain were normal. Subsequent blood glucose values were within normal range. On follow-up after 7 days, the child was healthy with no recurrences of the symptoms. A provisional diagnosis of ondansetron-induced acute dystonia with seizures and hypoglycemia was made.
Discussion: Ondansetron is an antiemetic known for its safety profile. There have been a few case reports of extrapyramidal adverse effects and seizures from this drug but none of ondansetron-associated hypoglycemia. 5-Hydroxytryptamine (5-HT(3)) receptors are involved in arginine vasopressin-mediated release of adrenocorticotropin hormone and cortisol in response to stress. Blunting of this stress response by ondansetron, a 5-HT(3) receptor antagonist, could have caused the hypoglycemia in this patient. According to the Naranjo scale, ondansetron was probably the cause of the dystonia and seizures, and possibly the cause of the hypoglycemia. Other potential explanations for hypoglycemia were considered but were thought to be less likely.
Conclusions: Dystonia and seizures have been associated with ondansetron in a few case reports. In addition, clinicians need to consider hypoglycemia as a possible adverse effect of ondansetron.