Drug interactions
Moxifloxacin + Thioridazine
Severity: Contraindicated
Moxifloxacin and Thioridazine: contraindicated interaction.
Last updated Sources: UK SmPC
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 causes marked dose-related QT prolongation and its labeling contraindicates use with other drugs that prolong the QT interval, such as moxifloxacin. The combination carries a high risk of torsades de pointes and sudden cardiac death.
What this interaction means in plain words
Moxifloxacin 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.
Moxifloxacin belongs to Anti Bacterial; Thioridazine belongs to Central Nervous System.
Why it happens
Additive hERG potassium channel blockade causing marked delay in ventricular repolarization.
What to do
Do not combine; use an antibiotic without QT effects. Thioridazine should only be used under strict labeling conditions.
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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References
Other interactions of Moxifloxacin
- Amiodarone + Moxifloxacin Contraindicated
- Arsenic trioxide + Moxifloxacin Contraindicated
- Disopyramide + Moxifloxacin Contraindicated
- Dofetilide + Moxifloxacin Contraindicated
- Dronedarone + Moxifloxacin Contraindicated
- Droperidol + Moxifloxacin Contraindicated
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 Moxifloxacin with Thioridazine?
MediHelp rates the interaction as contraindicated. Moxifloxacin 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 causes marked dose-related QT prolongation and its labeling contraindicates use with other drugs that prolong the QT interval, such as moxifloxacin. The combination carries a high risk of torsades de pointes and sudden cardiac death.
How serious is the interaction between Moxifloxacin 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: Do not combine; use an antibiotic without QT effects. Thioridazine should only be used under strict labeling conditions.
What other medicines interact with Moxifloxacin?
MediHelp also lists interactions of Moxifloxacin with, for example, Amiodarone, Arsenic trioxide, Disopyramide. The full list is on the Moxifloxacin page.
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