Drug interactions
Amitriptyline + Belladonna alkaloids
Severity: Moderate
Amitriptyline and Belladonna alkaloids: 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
Amitriptyline has strong antimuscarinic activity, and belladonna alkaloids are antimuscarinic agents, so their effects add together. This can cause dry mouth, constipation, urinary retention, blurred vision, tachycardia, confusion and heat intolerance, especially in older adults.
What this interaction means in plain words
Amitriptyline and Belladonna alkaloids 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 blockade of muscarinic acetylcholine receptors.
What to do
Monitor for anticholinergic toxicity such as urinary retention, constipation, delirium and tachycardia. Reduce doses or choose a non-anticholinergic alternative in elderly patients or those with glaucoma or prostatic hypertrophy.
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 Amitriptyline
- Amitriptyline + Isocarboxazid Contraindicated
- Amitriptyline + Methylene blue Contraindicated
- Amitriptyline + Phenelzine Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amitriptyline + Procarbazine Contraindicated
- Amitriptyline + Safinamide Contraindicated
Frequently asked questions
Can I take Amitriptyline with Belladonna alkaloids?
MediHelp rates the interaction as moderate. Amitriptyline and Belladonna alkaloids 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. Amitriptyline has strong antimuscarinic activity, and belladonna alkaloids are antimuscarinic agents, so their effects add together. This can cause dry mouth, constipation, urinary retention, blurred vision, tachycardia, confusion and heat intolerance, especially in older adults.
How serious is the interaction between Amitriptyline and Belladonna alkaloids?
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 toxicity such as urinary retention, constipation, delirium and tachycardia. Reduce doses or choose a non-anticholinergic alternative in elderly patients or those with glaucoma or prostatic hypertrophy.
What other medicines interact with Amitriptyline?
MediHelp also lists interactions of Amitriptyline with, for example, Isocarboxazid, Methylene blue, Phenelzine. The full list is on the Amitriptyline page.
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