Drug interactions
Quinacrine + Thioridazine
Severity: Contraindicated
Quinacrine 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
Quinacrine may inhibit CYP2D6 and raise thioridazine concentrations. Thioridazine labeling contraindicates drugs that inhibit its metabolism because higher levels cause QT prolongation and potentially fatal arrhythmias.
What this interaction means in plain words
Quinacrine 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.
Why it happens
Inhibition of CYP2D6-mediated thioridazine metabolism, increasing exposure and QT risk.
What to do
Avoid the combination and use an alternative antiprotozoal or antipsychotic. If exposure has occurred, obtain an ECG and correct electrolytes.
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 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 Quinacrine with Thioridazine?
MediHelp rates the interaction as contraindicated. Quinacrine 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. Quinacrine may inhibit CYP2D6 and raise thioridazine concentrations. Thioridazine labeling contraindicates drugs that inhibit its metabolism because higher levels cause QT prolongation and potentially fatal arrhythmias.
How serious is the interaction between Quinacrine 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 and use an alternative antiprotozoal or antipsychotic. If exposure has occurred, obtain an ECG and correct electrolytes.
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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