Drug interactions
Propranolol + Thioridazine
Severity: Contraindicated
Propranolol and Thioridazine: contraindicated 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 can raise propranolol concentrations, and propranolol can raise thioridazine concentrations. Because thioridazine itself prolongs the QT interval, higher levels increase the risk of torsades de pointes and sudden death.
What this interaction means in plain words
Propranolol and Thioridazine are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Propranolol belongs to Cardiovascular; Thioridazine belongs to Central Nervous System.
Why it happens
Mutual metabolic inhibition involving CYP2D6, with additive cardiac depressant and proarrhythmic effects.
What to do
Avoid concurrent use. If a beta blocker is needed with thioridazine, select one not dependent on CYP2D6 such as atenolol, though thioridazine alternatives are preferred.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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Other interactions of Propranolol
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 Propranolol with Thioridazine?
MediHelp rates the interaction as contraindicated. Propranolol and Thioridazine are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Thioridazine can raise propranolol concentrations, and propranolol can raise thioridazine concentrations. Because thioridazine itself prolongs the QT interval, higher levels increase the risk of torsades de pointes and sudden death.
How serious is the interaction between Propranolol and Thioridazine?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid concurrent use. If a beta blocker is needed with thioridazine, select one not dependent on CYP2D6 such as atenolol, though thioridazine alternatives are preferred.
What other medicines interact with Propranolol?
MediHelp also lists interactions of Propranolol with, for example, Acebutolol, Adrenaline-articaine, Albuterol. The full list is on the Propranolol page.
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