Drug interactions
Thioridazine + Tramadol
Severity: Major
Thioridazine and Tramadol: 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 inhibits CYP2D6, which reduces conversion of tramadol to its active opioid metabolite O-desmethyltramadol, so analgesia may be weaker. Tramadol's parent drug exposure rises, which may increase serotonergic and seizure risk, and both drugs add to sedation. Thioridazine also prolongs the QT interval and lowers the seizure threshold, adding to tramadol's seizure risk.
What this interaction means in plain words
Thioridazine and Tramadol 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 belongs to Central Nervous System; Tramadol belongs to Musculoskeletal.
Why it happens
Thioridazine inhibits CYP2D6-mediated activation of tramadol, with additive CNS depression and additive seizure-threshold lowering.
What to do
Prefer a non-CYP2D6-dependent analgesic if possible. If combined, monitor analgesic response, sedation, seizure activity and ECG/QTc.
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 Tramadol
- Isocarboxazid + Tramadol Contraindicated
- Olanzapine / samidorphan + Tramadol Contraindicated
- Phenelzine + Tramadol Contraindicated
- Procarbazine + Tramadol Contraindicated
- Rasagiline + Tramadol Contraindicated
- Safinamide + Tramadol 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 Tramadol?
MediHelp rates the interaction as major. Thioridazine and Tramadol 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 inhibits CYP2D6, which reduces conversion of tramadol to its active opioid metabolite O-desmethyltramadol, so analgesia may be weaker. Tramadol's parent drug exposure rises, which may increase serotonergic and seizure risk, and both drugs add to sedation. Thioridazine also prolongs the QT interval and lowers the seizure threshold, adding to tramadol's seizure risk.
How serious is the interaction between Thioridazine and Tramadol?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Prefer a non-CYP2D6-dependent analgesic if possible. If combined, monitor analgesic response, sedation, seizure activity and ECG/QTc.
What other medicines interact with Tramadol?
MediHelp also lists interactions of Tramadol with, for example, Isocarboxazid, Olanzapine / samidorphan, Phenelzine. The full list is on the Tramadol page.
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