Drug interactions
Fenfluramine + Ondansetron
Severity: Minor
Fenfluramine and Ondansetron: minor interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Fenfluramine acts by releasing serotonin and activating serotonin receptors. Potent serotonin receptor antagonists such as ondansetron may in theory reduce its anticonvulsant effect, although the clinical significance is unconfirmed.
What this interaction means in plain words
Fenfluramine and Ondansetron have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Fenfluramine belongs to Central Nervous System; Ondansetron belongs to Gastrointestinal Tract.
Why it happens
Possible pharmacodynamic antagonism at serotonin receptors.
What to do
Monitor seizure frequency when ondansetron is used with fenfluramine. Consider an antiemetic with a different mechanism if seizure control worsens.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Ondansetron
- Apomorphine + Ondansetron Contraindicated
- Ondansetron + Thioridazine Contraindicated
- Ondansetron + Vandetanib Contraindicated
- Adagrasib + Ondansetron Major
- Amiodarone + Ondansetron Major
- Amisulpride + Ondansetron Major
Other interactions of Fenfluramine
- Fenfluramine + Isocarboxazid Contraindicated
- Fenfluramine + Linezolid Contraindicated
- Fenfluramine + Phenelzine Contraindicated
- Fenfluramine + Selegiline Contraindicated
- Fenfluramine + Tranylcypromine Contraindicated
- Almotriptan + Fenfluramine Major
Frequently asked questions
Can I take Fenfluramine with Ondansetron?
MediHelp rates the interaction as minor. Fenfluramine and Ondansetron have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Fenfluramine acts by releasing serotonin and activating serotonin receptors. Potent serotonin receptor antagonists such as ondansetron may in theory reduce its anticonvulsant effect, although the clinical significance is unconfirmed.
How serious is the interaction between Fenfluramine and Ondansetron?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor seizure frequency when ondansetron is used with fenfluramine. Consider an antiemetic with a different mechanism if seizure control worsens.
What other medicines interact with Ondansetron?
MediHelp also lists interactions of Ondansetron with, for example, Apomorphine, Thioridazine, Vandetanib. The full list is on the Ondansetron page.
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