Drug interactions
Methyldopa + Olanzapine / samidorphan
Severity: Moderate
Methyldopa and Olanzapine / samidorphan: 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 can cause orthostatic hypotension, so it may add to the blood pressure lowering effect of methyldopa. Dizziness, syncope and falls are the main risks, especially during initiation.
What this interaction means in plain words
Methyldopa and Olanzapine / samidorphan 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 hypotension from olanzapine alpha-1 adrenergic antagonism and methyldopa sympatholysis.
What to do
Monitor blood pressure including orthostatic readings when starting olanzapine/samidorphan, and reduce the methyldopa dose if hypotension occurs.
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 Methyldopa and Olanzapine / samidorphan, 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 7 days on the web. No card needed.
Other interactions of Methyldopa
- Methyldopa + Tranylcypromine Contraindicated
- Iobenguane i + Methyldopa Major
- Lofexidine + Methyldopa Major
- Methyldopa + Pexidartinib Major
- Methyldopa + Pretomanid Major
- Methyldopa + Thioridazine Major
Frequently asked questions
Can I take Methyldopa with Olanzapine / samidorphan?
MediHelp rates the interaction as moderate. Methyldopa and Olanzapine / samidorphan 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 can cause orthostatic hypotension, so it may add to the blood pressure lowering effect of methyldopa. Dizziness, syncope and falls are the main risks, especially during initiation.
How serious is the interaction between Methyldopa and Olanzapine / samidorphan?
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 blood pressure including orthostatic readings when starting olanzapine/samidorphan, and reduce the methyldopa dose if hypotension occurs.
What other medicines interact with Methyldopa?
MediHelp also lists interactions of Methyldopa with, for example, Tranylcypromine, Iobenguane i, Lofexidine. The full list is on the Methyldopa 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.
