Drug interactions
Saquinavir + Thioridazine
Severity: Contraindicated
Saquinavir 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
Saquinavir prolongs the QT interval and is a CYP3A4 inhibitor, and thioridazine is highly arrhythmogenic. Their combination can cause torsades de pointes.
What this interaction means in plain words
Saquinavir 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
Additive QTc prolongation, with possible pharmacokinetic increases in exposure.
What to do
Do not coadminister; select an alternative antiretroviral or antipsychotic.
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 Saquinavir with Thioridazine?
MediHelp rates the interaction as contraindicated. Saquinavir 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. Saquinavir prolongs the QT interval and is a CYP3A4 inhibitor, and thioridazine is highly arrhythmogenic. Their combination can cause torsades de pointes.
How serious is the interaction between Saquinavir 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: Do not coadminister; select an alternative antiretroviral or antipsychotic.
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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