Drug interactions
Amoxapine + Trihexyphenidyl
Severity: Moderate
Amoxapine 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
Amoxapine, a tricyclic-type antidepressant, has anticholinergic activity that adds to trihexyphenidyl. This increases the risk of urinary retention, constipation, tachycardia, blurred vision and confusion, especially in older adults.
What this interaction means in plain words
Amoxapine 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.
Why it happens
Additive muscarinic antagonism.
What to do
Monitor for central and peripheral anticholinergic toxicity and use the lowest effective doses. Consider a less anticholinergic antidepressant if toxicity develops.
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 Trihexyphenidyl
Frequently asked questions
Can I take Amoxapine with Trihexyphenidyl?
MediHelp rates the interaction as moderate. Amoxapine 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. Amoxapine, a tricyclic-type antidepressant, has anticholinergic activity that adds to trihexyphenidyl. This increases the risk of urinary retention, constipation, tachycardia, blurred vision and confusion, especially in older adults.
How serious is the interaction between Amoxapine 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: Monitor for central and peripheral anticholinergic toxicity and use the lowest effective doses. Consider a less anticholinergic antidepressant if toxicity develops.
What other medicines interact with Trihexyphenidyl?
MediHelp also lists interactions of Trihexyphenidyl with, for example, Orphenadrin, Oxybutynin, Scopolamine. The full list is on the Trihexyphenidyl page.
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