Drug interactions
Doxepin + Hydroxyzine
Severity: Major
Doxepin and Hydroxyzine: major interaction.
Last updated Sources: US FDA label
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 are sedating and anticholinergic, and both can prolong the QT interval. Combined use increases drowsiness, anticholinergic effects and the potential for QT prolongation and arrhythmia, especially with other risk factors.
What this interaction means in plain words
Doxepin and Hydroxyzine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Doxepin belongs to Dermatology; Hydroxyzine belongs to Respiratory.
Why it happens
Additive central H1 antagonism and antimuscarinic effects, plus additive blockade of cardiac potassium channels prolonging repolarization.
What to do
Avoid the combination in patients with QT risk factors, and obtain an ECG and check potassium and magnesium if it is needed. Use the lowest doses and monitor for sedation and anticholinergic effects.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Hydroxyzine
- Droperidol + Hydroxyzine Contraindicated
- Hydroxyzine + Pimozide Contraindicated
- Hydroxyzine + Thioridazine Contraindicated
- Hydroxyzine + Vandetanib Contraindicated
- Alfentanil + Hydroxyzine Major
- Amiodarone + Hydroxyzine 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 Hydroxyzine?
MediHelp rates the interaction as major. Doxepin and Hydroxyzine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Both drugs are sedating and anticholinergic, and both can prolong the QT interval. Combined use increases drowsiness, anticholinergic effects and the potential for QT prolongation and arrhythmia, especially with other risk factors.
How serious is the interaction between Doxepin and Hydroxyzine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination in patients with QT risk factors, and obtain an ECG and check potassium and magnesium if it is needed. Use the lowest doses and monitor for sedation and anticholinergic effects.
What other medicines interact with Hydroxyzine?
MediHelp also lists interactions of Hydroxyzine with, for example, Droperidol, Pimozide, Thioridazine. The full list is on the Hydroxyzine page.
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