Drug interactions
Cyproheptadine + Doxylamine
Severity: Moderate
Cyproheptadine and Doxylamine: 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, so the combination can cause excessive drowsiness, impaired alertness and anticholinergic effects. Doxylamine is often present in over-the-counter sleep and cold products, which makes unintended duplication likely.
What this interaction means in plain words
Cyproheptadine and Doxylamine 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.
Cyproheptadine belongs to Respiratory; Doxylamine belongs to Respiratory.
Why it happens
Additive H1 antagonism, CNS depression and anticholinergic activity.
What to do
Avoid combining the two and check for hidden doxylamine in OTC products. Monitor for oversedation and anticholinergic effects if both are used.
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 Cyproheptadine
- Cyproheptadine + Isocarboxazid Contraindicated
- Cyproheptadine + Phenelzine Contraindicated
- Cyproheptadine + Tranylcypromine Contraindicated
- Alfentanil + Cyproheptadine Major
- Belladonna and opium + Cyproheptadine Major
- Benzhydrocodone / acetaminophen + Cyproheptadine Major
Other interactions of Doxylamine
Frequently asked questions
Can I take Cyproheptadine with Doxylamine?
MediHelp rates the interaction as moderate. Cyproheptadine and Doxylamine 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, so the combination can cause excessive drowsiness, impaired alertness and anticholinergic effects. Doxylamine is often present in over-the-counter sleep and cold products, which makes unintended duplication likely.
How serious is the interaction between Cyproheptadine and Doxylamine?
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 combining the two and check for hidden doxylamine in OTC products. Monitor for oversedation and anticholinergic effects if both are used.
What other medicines interact with Cyproheptadine?
MediHelp also lists interactions of Cyproheptadine with, for example, Isocarboxazid, Phenelzine, Tranylcypromine. The full list is on the Cyproheptadine page.
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