Drug interactions
Iloperidone + Thioridazine
Severity: Contraindicated
Iloperidone 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
Both antipsychotics prolong the QT interval, and thioridazine also inhibits CYP2D6, which raises iloperidone concentrations. Together this markedly increases the risk of torsades de pointes, and additive sedation and extrapyramidal effects can also occur.
What this interaction means in plain words
Iloperidone 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.
Iloperidone belongs to Central Nervous System; Thioridazine belongs to Central Nervous System.
Why it happens
Additive QT prolongation, plus CYP2D6 inhibition by thioridazine that increases iloperidone exposure.
What to do
Avoid combining these drugs; use an antipsychotic with lower QT liability and do not co-prescribe two QT-prolonging antipsychotics.
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
Other interactions of Iloperidone
Frequently asked questions
Can I take Iloperidone with Thioridazine?
MediHelp rates the interaction as contraindicated. Iloperidone 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. Both antipsychotics prolong the QT interval, and thioridazine also inhibits CYP2D6, which raises iloperidone concentrations. Together this markedly increases the risk of torsades de pointes, and additive sedation and extrapyramidal effects can also occur.
How serious is the interaction between Iloperidone 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 combining these drugs; use an antipsychotic with lower QT liability and do not co-prescribe two QT-prolonging antipsychotics.
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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