Drug interactions
Belladonna alkaloids + Olanzapine
Severity: Moderate
Belladonna alkaloids and Olanzapine: 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
Olanzapine has anticholinergic activity, so adding belladonna alkaloids can produce additive effects such as dry mouth, constipation, urinary retention, blurred vision, tachycardia and confusion. Elderly patients are at particular risk of delirium and severe constipation or ileus.
What this interaction means in plain words
Belladonna alkaloids and Olanzapine 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 receptor antagonism.
What to do
Monitor for anticholinergic toxicity, bowel function and urinary retention, and use the lowest effective doses. Avoid in elderly patients or those with narrow-angle glaucoma or ileus risk where possible.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Belladonna alkaloids and Olanzapine, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
Other interactions of Olanzapine
Frequently asked questions
Can I take Belladonna alkaloids with Olanzapine?
MediHelp rates the interaction as moderate. Belladonna alkaloids and Olanzapine 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. Olanzapine has anticholinergic activity, so adding belladonna alkaloids can produce additive effects such as dry mouth, constipation, urinary retention, blurred vision, tachycardia and confusion. Elderly patients are at particular risk of delirium and severe constipation or ileus.
How serious is the interaction between Belladonna alkaloids and Olanzapine?
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, bowel function and urinary retention, and use the lowest effective doses. Avoid in elderly patients or those with narrow-angle glaucoma or ileus risk where possible.
What other medicines interact with Olanzapine?
MediHelp also lists interactions of Olanzapine with, for example, Amisulpride, Amoxapine, Apomorphine. The full list is on the Olanzapine page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
