Drug interactions
Pimozide + Trihexyphenidyl
Severity: Moderate
Pimozide and Trihexyphenidyl: 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 drugs have anticholinergic activity, so combined use can cause dry mouth, constipation, urinary retention, blurred vision, confusion and tachycardia. Anticholinergics are also sometimes given alongside antipsychotics to treat extrapyramidal symptoms, so this combination is common and usually manageable.
What this interaction means in plain words
Pimozide and Trihexyphenidyl 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.
Pimozide belongs to Central Nervous System; Trihexyphenidyl belongs to Central Nervous System.
Why it happens
Additive muscarinic receptor antagonism.
What to do
Use the lowest effective trihexyphenidyl dose and monitor for anticholinergic toxicity, especially in older patients. Reassess the need for it regularly.
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 Pimozide
- Adagrasib + Pimozide Contraindicated
- Amiodarone + Pimozide Contraindicated
- Amisulpride + Pimozide Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amoxapine + Pimozide Contraindicated
- Anagrelide + Pimozide Contraindicated
Other interactions of Trihexyphenidyl
Frequently asked questions
Can I take Pimozide with Trihexyphenidyl?
MediHelp rates the interaction as moderate. Pimozide and Trihexyphenidyl 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 drugs have anticholinergic activity, so combined use can cause dry mouth, constipation, urinary retention, blurred vision, confusion and tachycardia. Anticholinergics are also sometimes given alongside antipsychotics to treat extrapyramidal symptoms, so this combination is common and usually manageable.
How serious is the interaction between Pimozide and Trihexyphenidyl?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use the lowest effective trihexyphenidyl dose and monitor for anticholinergic toxicity, especially in older patients. Reassess the need for it regularly.
What other medicines interact with Pimozide?
MediHelp also lists interactions of Pimozide with, for example, Adagrasib, Amiodarone, Amisulpride. The full list is on the Pimozide page.
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