Drug interactions
Thioridazine + Trospium
Severity: Major
Thioridazine and Trospium: 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
Thioridazine has strong anticholinergic activity, which adds substantially to the effects of trospium. Constipation, urinary retention, dry mouth, confusion and tachycardia are more likely, and thioridazine also carries a serious QT prolongation risk.
What this interaction means in plain words
Thioridazine and Trospium 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.
Thioridazine belongs to Central Nervous System; Trospium belongs to Genitourinary.
Why it happens
Additive antimuscarinic pharmacodynamic effects.
What to do
Avoid the combination where possible, especially in older patients. If used, monitor anticholinergic effects and ECG with electrolytes as required for thioridazine.
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 Trospium
- Clozapine + Trospium Major
- Pramlintide + Trospium Major
- Trihexyphenidyl + Trospium Major
- Aclidinium + Trospium Moderate
- Amantadine + Trospium Moderate
- Amitriptyline + Trospium Moderate
Other interactions of Thioridazine
- Abiraterone + Thioridazine Contraindicated
- Adagrasib + Thioridazine Contraindicated
- Amiodarone + Thioridazine Contraindicated
- Amisulpride + Thioridazine Contraindicated
- Amitriptyline + Thioridazine Contraindicated
- Amoxapine + Thioridazine Contraindicated
Frequently asked questions
Can I take Thioridazine with Trospium?
MediHelp rates the interaction as major. Thioridazine and Trospium 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. Thioridazine has strong anticholinergic activity, which adds substantially to the effects of trospium. Constipation, urinary retention, dry mouth, confusion and tachycardia are more likely, and thioridazine also carries a serious QT prolongation risk.
How serious is the interaction between Thioridazine and Trospium?
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 where possible, especially in older patients. If used, monitor anticholinergic effects and ECG with electrolytes as required for thioridazine.
What other medicines interact with Trospium?
MediHelp also lists interactions of Trospium with, for example, Clozapine, Pramlintide, Trihexyphenidyl. The full list is on the Trospium page.
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