Drug interactions
Metoprolol + Thioridazine
Severity: Contraindicated
Metoprolol 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 inhibits CYP2D6 and can markedly increase metoprolol exposure, causing bradycardia and hypotension. Elevated thioridazine levels may also occur, adding to the QT prolongation and arrhythmia risk.
What this interaction means in plain words
Metoprolol 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.
Metoprolol belongs to Cardiovascular; Thioridazine belongs to Central Nervous System.
Why it happens
Inhibition of CYP2D6-mediated metabolism of metoprolol, with additive cardiac effects.
What to do
Avoid the combination; use a safer antipsychotic or a beta blocker not metabolized by CYP2D6. If it cannot be avoided, monitor ECG and heart rate closely.
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 Metoprolol
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 Metoprolol with Thioridazine?
MediHelp rates the interaction as contraindicated. Metoprolol 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 inhibits CYP2D6 and can markedly increase metoprolol exposure, causing bradycardia and hypotension. Elevated thioridazine levels may also occur, adding to the QT prolongation and arrhythmia risk.
How serious is the interaction between Metoprolol 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 the combination; use a safer antipsychotic or a beta blocker not metabolized by CYP2D6. If it cannot be avoided, monitor ECG and heart rate closely.
What other medicines interact with Metoprolol?
MediHelp also lists interactions of Metoprolol with, for example, Amifostine, Amiodarone, Atenolol-chlorthalidone. The full list is on the Metoprolol page.
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