Drug interactions
Clozapine + Doxylamine
Severity: Moderate
Clozapine 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
Doxylamine is a sedating antihistamine with anticholinergic effects, so with clozapine it increases drowsiness and anticholinergic effects including constipation and urinary retention.
What this interaction means in plain words
Clozapine 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.
Clozapine belongs to Central Nervous System; Doxylamine belongs to Respiratory.
Why it happens
Additive H1 antagonism and antimuscarinic effects.
What to do
Monitor sedation and bowel function, and avoid regular use of doxylamine as a sleep aid. Consider non-anticholinergic alternatives.
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 Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Other interactions of Doxylamine
Frequently asked questions
Can I take Clozapine with Doxylamine?
MediHelp rates the interaction as moderate. Clozapine 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. Doxylamine is a sedating antihistamine with anticholinergic effects, so with clozapine it increases drowsiness and anticholinergic effects including constipation and urinary retention.
How serious is the interaction between Clozapine 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: Monitor sedation and bowel function, and avoid regular use of doxylamine as a sleep aid. Consider non-anticholinergic alternatives.
What other medicines interact with Clozapine?
MediHelp also lists interactions of Clozapine with, for example, Deferiprone, Irinotecan, Pimozide. The full list is on the Clozapine page.
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