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Ondansetron and seizures
Niranjan N Singh1, Ajitesh Rai, John B Selhorst
1Department of Neurology, University of Missouri, Columbia, Missouri, USA. singhn@health.missouri.edu
Abstract:
Experimental studies suggest that 5-hydroxytryptamine (5-HT) receptors play a role in epileptogenesis and seizure propagation. Ondansetron, a 5-HT(3) receptor antagonist, has been reported to have proconvulsant and anticonvulsant effects in animals. We describe three patients who developed seizures after receiving ondansetron. There were two females and one male. Ages ranged from 38-56 years. None had a previous or family history of seizures. Four milligrams (mg) of ondansetron was given intravenously for severe nausea and vomiting in association with migraine, gastritis, and diabetic ketoacidosis. A generalized tonic-clonic seizure occurred in each patient--12, 15, and 22 min after injection. Brain magnetic resonance imaging (MRI) and electroencephalography (EEG) were normal in all patients. Although no antiepileptic drugs were given, none had seizure recurrence subsequently. The temporal relationship between ondansetron administration and seizures, lack of EEG or MRI abnormalities, and absence of seizure recurrence suggest that the seizures were causally related to ondansetron in our patients.
Insights
Ondansetron, a 5-HT(3) receptor antagonist, may trigger seizures in susceptible individuals. This case series highlights three patients experiencing seizures shortly after ondansetron administration, with no recurrence observed.
Area of Science:
- Neuroscience
- Pharmacology
- Clinical Neurology
Background:
- 5-hydroxytryptamine (5-HT) receptors are implicated in epileptogenesis.
- Ondansetron, a 5-HT(3) receptor antagonist, exhibits variable effects on seizures in animal models.
- The potential for ondansetron to induce seizures in humans requires further investigation.
Purpose of the Study:
- To report cases of seizures occurring after ondansetron administration.
- To investigate the potential causal link between ondansetron and seizure induction.
Main Methods:
- Case series describing three patients who experienced seizures post-ondansetron.
- Clinical assessment including electroencephalography (EEG) and magnetic resonance imaging (MRI).
- Evaluation of seizure recurrence after ondansetron cessation.
Main Results:
- Three patients (2 female, 1 male; ages 38-56) developed generalized tonic-clonic seizures 12-22 minutes after intravenous ondansetron (4 mg).
- None had prior seizure history or family history of epilepsy.
- EEG and MRI were normal; no seizures recurred after discontinuation of ondansetron.
Conclusions:
- The temporal association and lack of recurrence suggest ondansetron may have triggered seizures in these patients.
- Ondansetron should be used cautiously in patients with potential seizure risk factors.
- Further research is warranted to elucidate the mechanism of ondansetron-induced seizures.
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Seizures: Classification
Seizures are typically classified into two main categories: focal and generalized seizures.
Focal Seizures
Focal seizures originate from specific regions of the brain. These seizures are further sub-classified into two types:
