Drug interactions
Belladonna and opium + Trihexyphenidyl
Severity: Moderate
Belladonna and opium 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
Belladonna contributes antimuscarinic activity, and combined with trihexyphenidyl this can produce marked anticholinergic effects. The opium component adds constipation and sedation, raising the risk of severe constipation, ileus, urinary retention and confusion.
What this interaction means in plain words
Belladonna and opium 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 antimuscarinic effects, with opioid-related reduction in gut motility and CNS depression compounding the problem.
What to do
Monitor bowel function, urinary output and mental status, and use the lowest effective doses for the shortest time; stop or lower doses if retention, ileus or delirium emerges.
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 Belladonna and opium with Trihexyphenidyl?
MediHelp rates the interaction as moderate. Belladonna and opium 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. Belladonna contributes antimuscarinic activity, and combined with trihexyphenidyl this can produce marked anticholinergic effects. The opium component adds constipation and sedation, raising the risk of severe constipation, ileus, urinary retention and confusion.
How serious is the interaction between Belladonna and opium 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 bowel function, urinary output and mental status, and use the lowest effective doses for the shortest time; stop or lower doses if retention, ileus or delirium emerges.
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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