Drug interactions
Chlorpromazine + Homatropine
Severity: Moderate
Chlorpromazine and Homatropine: 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
Homatropine is an antimuscarinic and adds to the anticholinergic effects of chlorpromazine. This can produce dry mouth, constipation, urinary retention, blurred vision and confusion, with greater risk in older patients.
What this interaction means in plain words
Chlorpromazine and Homatropine 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.
Chlorpromazine belongs to Central Nervous System; Homatropine belongs to Genitourinary.
Why it happens
Additive antimuscarinic pharmacodynamic effects.
What to do
Monitor for anticholinergic adverse effects such as constipation, urinary retention and cognitive changes. Use the lowest effective doses or choose a non-anticholinergic alternative.
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 Chlorpromazine
- Chlorpromazine + Dofetilide Contraindicated
- Chlorpromazine + Dronedarone Contraindicated
- Chlorpromazine + Droperidol Contraindicated
- Chlorpromazine + Ibutilide Contraindicated
- Chlorpromazine + Metrizamide Contraindicated
- Chlorpromazine + Panobinostat Contraindicated
Other interactions of Homatropine
- Amantadine + Homatropine Moderate
- Amitriptyline + Homatropine Moderate
- Atropine + Homatropine Moderate
- Benztropine + Homatropine Moderate
- Bethanechol + Homatropine Moderate
- Clomipramine + Homatropine Moderate
Frequently asked questions
Can I take Chlorpromazine with Homatropine?
MediHelp rates the interaction as moderate. Chlorpromazine and Homatropine 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. Homatropine is an antimuscarinic and adds to the anticholinergic effects of chlorpromazine. This can produce dry mouth, constipation, urinary retention, blurred vision and confusion, with greater risk in older patients.
How serious is the interaction between Chlorpromazine and Homatropine?
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 anticholinergic adverse effects such as constipation, urinary retention and cognitive changes. Use the lowest effective doses or choose a non-anticholinergic alternative.
What other medicines interact with Chlorpromazine?
MediHelp also lists interactions of Chlorpromazine with, for example, Dofetilide, Dronedarone, Droperidol. The full list is on the Chlorpromazine page.
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