Drug interactions
Meclizine + Trihexyphenidyl
Severity: Moderate
Meclizine 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
Meclizine has antimuscarinic and sedating properties that add to those of trihexyphenidyl. This may cause dry mouth, blurred vision, urinary retention, constipation, drowsiness and confusion.
What this interaction means in plain words
Meclizine 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.
Meclizine belongs to Respiratory; Trihexyphenidyl belongs to Central Nervous System.
Why it happens
Additive antimuscarinic effects.
What to do
Monitor for anticholinergic adverse effects, particularly in older adults. Consider a non-anticholinergic option for vertigo or nausea if symptoms occur.
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
Other interactions of Meclizine
Frequently asked questions
Can I take Meclizine with Trihexyphenidyl?
MediHelp rates the interaction as moderate. Meclizine 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. Meclizine has antimuscarinic and sedating properties that add to those of trihexyphenidyl. This may cause dry mouth, blurred vision, urinary retention, constipation, drowsiness and confusion.
How serious is the interaction between Meclizine 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 anticholinergic adverse effects, particularly in older adults. Consider a non-anticholinergic option for vertigo or nausea if symptoms occur.
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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