Drug interactions
Risperidone + Thioridazine
Severity: Major
Risperidone 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
Both agents prolong the QT interval and block dopamine receptors, raising the risk of torsades de pointes, extrapyramidal symptoms and sedation. Thioridazine also inhibits CYP2D6, which can raise risperidone exposure.
What this interaction means in plain words
Risperidone 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.
Risperidone belongs to Central Nervous System; Thioridazine belongs to Central Nervous System.
Why it happens
Additive QT prolongation and D2 antagonism, plus CYP2D6 inhibition by thioridazine increasing risperidone levels.
What to do
Avoid the combination if possible; otherwise monitor ECG and electrolytes and use the lowest effective risperidone dose.
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
Other interactions of Risperidone
- Ibutilide + Risperidone Contraindicated
- Risperidone + Vandetanib Contraindicated
- Adagrasib + Risperidone Major
- Amiodarone + Risperidone Major
- Amisulpride + Risperidone Major
- Amoxapine + Risperidone Major
Frequently asked questions
Can I take Risperidone with Thioridazine?
MediHelp rates the interaction as major. Risperidone 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. Both agents prolong the QT interval and block dopamine receptors, raising the risk of torsades de pointes, extrapyramidal symptoms and sedation. Thioridazine also inhibits CYP2D6, which can raise risperidone exposure.
How serious is the interaction between Risperidone 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: Avoid the combination if possible; otherwise monitor ECG and electrolytes and use the lowest effective risperidone dose.
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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