Drug interactions
Doxepin + Ondansetron
Severity: Moderate
Doxepin and Ondansetron: moderate 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
Both agents have been associated with serotonin syndrome in rare reports, and doxepin also has QT-prolonging potential at higher doses. The combination may cause agitation, tremor, hyperreflexia, hyperthermia, and arrhythmia in susceptible patients.
What this interaction means in plain words
Doxepin and Ondansetron can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Doxepin belongs to Dermatology; Ondansetron belongs to Gastrointestinal Tract.
Why it happens
Possible additive serotonergic effects (5-HT3 antagonism with reuptake inhibition) plus additive QT effects; the serotonergic mechanism is not firmly established.
What to do
Monitor for signs of serotonin toxicity and QT prolongation, particularly at higher doses or in patients with other risk factors. Consider an alternative antiemetic if symptoms occur or if the patient has cardiac risk factors.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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 Doxepin
- Doxepin + Isocarboxazid Contraindicated
- Doxepin + Phenelzine Contraindicated
- Doxepin + Procarbazine Contraindicated
- Doxepin + Safinamide Contraindicated
- Doxepin + Selegiline Contraindicated
- Doxepin + Tranylcypromine Contraindicated
Frequently asked questions
Can I take Doxepin with Ondansetron?
MediHelp rates the interaction as moderate. Doxepin and Ondansetron can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Both agents have been associated with serotonin syndrome in rare reports, and doxepin also has QT-prolonging potential at higher doses. The combination may cause agitation, tremor, hyperreflexia, hyperthermia, and arrhythmia in susceptible patients.
How serious is the interaction between Doxepin and Ondansetron?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for signs of serotonin toxicity and QT prolongation, particularly at higher doses or in patients with other risk factors. Consider an alternative antiemetic if symptoms occur or if the patient has cardiac risk factors.
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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