Drug interactions
Doxepin + Granisetron
Severity: Moderate
Doxepin and Granisetron: 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 drugs have been associated with serotonin syndrome in rare reports, and doxepin can also prolong the QT interval at higher doses, as can granisetron. Serious outcomes are uncommon, but the combination may need attention in patients on other serotonergic or QT-prolonging drugs.
What this interaction means in plain words
Doxepin and Granisetron 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; Granisetron belongs to Gastrointestinal Tract.
Why it happens
Possible additive serotonergic effect and additive QT prolongation; the serotonergic contribution of 5-HT3 antagonists is not well established.
What to do
Monitor for agitation, tremor, hyperreflexia, and fever, and obtain an ECG if cardiac risk factors exist. Keep doxepin at the lowest effective dose and correct electrolytes.
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 Granisetron
- Apomorphine + Granisetron Contraindicated
- Amiodarone + Granisetron Major
- Amisulpride + Granisetron Major
- Arsenic trioxide + Granisetron Major
- Artemether / lumefantrine + Granisetron Major
- Artemether + Granisetron 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 Granisetron?
MediHelp rates the interaction as moderate. Doxepin and Granisetron 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 drugs have been associated with serotonin syndrome in rare reports, and doxepin can also prolong the QT interval at higher doses, as can granisetron. Serious outcomes are uncommon, but the combination may need attention in patients on other serotonergic or QT-prolonging drugs.
How serious is the interaction between Doxepin and Granisetron?
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 agitation, tremor, hyperreflexia, and fever, and obtain an ECG if cardiac risk factors exist. Keep doxepin at the lowest effective dose and correct electrolytes.
What other medicines interact with Granisetron?
MediHelp also lists interactions of Granisetron with, for example, Apomorphine, Amiodarone, Amisulpride. The full list is on the Granisetron page.
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