Drug interactions
Clemastine + Thioridazine
Severity: Moderate
Clemastine and Thioridazine: 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
Clemastine is a sedating antihistamine with notable anticholinergic activity, as is thioridazine. Combined use may cause excess drowsiness, confusion, dry mouth, constipation and urinary retention. Older adults are at greatest risk.
What this interaction means in plain words
Clemastine and Thioridazine 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.
Clemastine belongs to Respiratory; Thioridazine belongs to Central Nervous System.
Why it happens
Additive H1 receptor blockade and muscarinic antagonism.
What to do
Switch to a non-sedating antihistamine where possible. If combined, monitor for oversedation and anticholinergic toxicity.
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 Clemastine and Thioridazine, 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 Thioridazine
- Abiraterone + Thioridazine Contraindicated
- Adagrasib + Thioridazine Contraindicated
- Amiodarone + Thioridazine Contraindicated
- Amisulpride + Thioridazine Contraindicated
- Amitriptyline + Thioridazine Contraindicated
- Amoxapine + Thioridazine Contraindicated
Other interactions of Clemastine
Frequently asked questions
Can I take Clemastine with Thioridazine?
MediHelp rates the interaction as moderate. Clemastine and Thioridazine 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. Clemastine is a sedating antihistamine with notable anticholinergic activity, as is thioridazine. Combined use may cause excess drowsiness, confusion, dry mouth, constipation and urinary retention. Older adults are at greatest risk.
How serious is the interaction between Clemastine and Thioridazine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Switch to a non-sedating antihistamine where possible. If combined, monitor for oversedation and anticholinergic toxicity.
What other medicines interact with Thioridazine?
MediHelp also lists interactions of Thioridazine with, for example, Abiraterone, Adagrasib, Amiodarone. The full list is on the Thioridazine 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.
