Drug interactions
Methylenedioxymethamphetamine + Thioridazine
Severity: Major
Methylenedioxymethamphetamine and Thioridazine: 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
MDMA is a sympathomimetic that can cause tachycardia, hyperthermia, electrolyte disturbances and arrhythmias, and thioridazine markedly prolongs the QT interval. Combined use may raise the risk of torsades de pointes and sudden cardiac death.
What this interaction means in plain words
Methylenedioxymethamphetamine and Thioridazine 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.
Why it happens
Additive proarrhythmic effects from thioridazine QT prolongation and MDMA sympathomimetic cardiotoxicity; MDMA may also inhibit CYP2D6, which metabolizes thioridazine.
What to do
Advise patients to avoid MDMA while taking thioridazine. If exposure has occurred, obtain an ECG and check electrolytes, with cardiac monitoring if symptomatic.
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 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 Methylenedioxymethamphetamine with Thioridazine?
MediHelp rates the interaction as major. Methylenedioxymethamphetamine and Thioridazine 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. MDMA is a sympathomimetic that can cause tachycardia, hyperthermia, electrolyte disturbances and arrhythmias, and thioridazine markedly prolongs the QT interval. Combined use may raise the risk of torsades de pointes and sudden cardiac death.
How serious is the interaction between Methylenedioxymethamphetamine and Thioridazine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Advise patients to avoid MDMA while taking thioridazine. If exposure has occurred, obtain an ECG and check electrolytes, with cardiac monitoring if symptomatic.
What other medicines interact with Thioridazine?
MediHelp also lists interactions of Thioridazine with, for example, Abiraterone, Adagrasib, Amiodarone. The full list is on the Thioridazine page.
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