Drug interactions
Scopolamine + Thioridazine
Severity: Major
Scopolamine and Thioridazine: 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 and sedative properties, so scopolamine can add substantially to dry mouth, constipation, urinary retention, confusion and tachycardia. Tachycardia and other anticholinergic effects may be poorly tolerated in a patient who already has a QT-prolonging drug on board.
What this interaction means in plain words
Scopolamine and Thioridazine 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.
Scopolamine belongs to Respiratory; Thioridazine belongs to Central Nervous System.
Why it happens
Additive muscarinic receptor blockade and CNS depression.
What to do
Avoid the combination in elderly patients and those with urinary retention or glaucoma. Otherwise monitor for anticholinergic toxicity and consider an ECG.
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 Scopolamine
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 Scopolamine with Thioridazine?
MediHelp rates the interaction as major. Scopolamine and Thioridazine 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 and sedative properties, so scopolamine can add substantially to dry mouth, constipation, urinary retention, confusion and tachycardia. Tachycardia and other anticholinergic effects may be poorly tolerated in a patient who already has a QT-prolonging drug on board.
How serious is the interaction between Scopolamine and Thioridazine?
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 in elderly patients and those with urinary retention or glaucoma. Otherwise monitor for anticholinergic toxicity and consider an ECG.
What other medicines interact with Scopolamine?
MediHelp also lists interactions of Scopolamine with, for example, Benzhydrocodone / acetaminophen, Buprenorphine long-acting, Buprenorphine subdermal implant. The full list is on the Scopolamine page.
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