Drug interactions
Thioridazine + Trazodone
Severity: Contraindicated
Thioridazine and Trazodone: 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 causes marked dose-related QT prolongation and is contraindicated with other drugs that prolong QT. Adding trazodone further increases the risk of torsades de pointes and sudden death.
What this interaction means in plain words
Thioridazine and Trazodone 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 belongs to Central Nervous System; Trazodone belongs to Central Nervous System.
Why it happens
Additive QT prolongation; thioridazine has strong potassium channel blockade.
What to do
Avoid the combination and choose an alternative antidepressant or antipsychotic. If a patient is on both, review therapy urgently with ECG and electrolyte checks.
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 Trazodone
- Arsenic trioxide + Trazodone Contraindicated
- Ibutilide + Trazodone Contraindicated
- Isocarboxazid + Trazodone Contraindicated
- Levoketoconazole + Trazodone Contraindicated
- Methylene blue + Trazodone Contraindicated
- Phenelzine + Trazodone 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 Thioridazine with Trazodone?
MediHelp rates the interaction as contraindicated. Thioridazine and Trazodone 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 is contraindicated with other drugs that prolong QT. Adding trazodone further increases the risk of torsades de pointes and sudden death.
How serious is the interaction between Thioridazine and Trazodone?
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 and choose an alternative antidepressant or antipsychotic. If a patient is on both, review therapy urgently with ECG and electrolyte checks.
What other medicines interact with Trazodone?
MediHelp also lists interactions of Trazodone with, for example, Arsenic trioxide, Ibutilide, Isocarboxazid. The full list is on the Trazodone page.
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