Drug interactions
Doxylamine + Hydroxyzine
Severity: Moderate
Doxylamine and Hydroxyzine: 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 are sedating first-generation antihistamines with anticholinergic activity, so combining them increases drowsiness, confusion and anticholinergic effects. Hydroxyzine also has a QT-prolongation liability.
What this interaction means in plain words
Doxylamine and Hydroxyzine 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.
Doxylamine belongs to Respiratory; Hydroxyzine belongs to Respiratory.
Why it happens
Duplicate H1 antagonism with additive CNS depression and anticholinergic effects.
What to do
Avoid concurrent use; choose a single agent. Monitor older patients for delirium, falls and urinary retention.
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 Doxylamine
Other interactions of Hydroxyzine
- Droperidol + Hydroxyzine Contraindicated
- Hydroxyzine + Pimozide Contraindicated
- Hydroxyzine + Thioridazine Contraindicated
- Hydroxyzine + Vandetanib Contraindicated
- Alfentanil + Hydroxyzine Major
- Amiodarone + Hydroxyzine Major
Frequently asked questions
Can I take Doxylamine with Hydroxyzine?
MediHelp rates the interaction as moderate. Doxylamine and Hydroxyzine 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 are sedating first-generation antihistamines with anticholinergic activity, so combining them increases drowsiness, confusion and anticholinergic effects. Hydroxyzine also has a QT-prolongation liability.
How serious is the interaction between Doxylamine and Hydroxyzine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid concurrent use; choose a single agent. Monitor older patients for delirium, falls and urinary retention.
What other medicines interact with Doxylamine?
MediHelp also lists interactions of Doxylamine with, for example, Belladonna and opium, Benzhydrocodone / acetaminophen, Brexanolone. The full list is on the Doxylamine page.
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