Drug interactions
Belladonna alkaloids + Clozapine
Severity: Major
Belladonna alkaloids and Clozapine: major 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 alkaloids are antimuscarinic and add to clozapine anticholinergic effects, raising the risk of constipation, ileus, urinary retention, tachycardia and delirium. Clozapine-related bowel hypomotility can become serious.
What this interaction means in plain words
Belladonna alkaloids and Clozapine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Additive antimuscarinic effects with reduced gastrointestinal motility.
What to do
Avoid the combination if possible. If necessary, monitor bowel function and urinary symptoms and treat constipation early.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Frequently asked questions
Can I take Belladonna alkaloids with Clozapine?
MediHelp rates the interaction as major. Belladonna alkaloids and Clozapine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Belladonna alkaloids are antimuscarinic and add to clozapine anticholinergic effects, raising the risk of constipation, ileus, urinary retention, tachycardia and delirium. Clozapine-related bowel hypomotility can become serious.
How serious is the interaction between Belladonna alkaloids and Clozapine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination if possible. If necessary, monitor bowel function and urinary symptoms and treat constipation early.
What other medicines interact with Clozapine?
MediHelp also lists interactions of Clozapine with, for example, Deferiprone, Irinotecan, Pimozide. The full list is on the Clozapine page.
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