Drug interactions
Cobicistat + Thioridazine
Severity: Contraindicated
Cobicistat and Thioridazine: contraindicated interaction.
Last updated Sources: US FDA label
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
Cobicistat strongly inhibits CYP3A and also inhibits CYP2D6, the main route of thioridazine clearance. Higher thioridazine concentrations can cause marked QTc prolongation, torsades de pointes and sudden death.
What this interaction means in plain words
Cobicistat 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.
Cobicistat belongs to Miscellaneous; Thioridazine belongs to Central Nervous System.
Why it happens
Cobicistat inhibits CYP2D6 and CYP3A4, reducing thioridazine metabolism and raising its plasma levels.
What to do
Avoid the combination and choose an antipsychotic with less QT risk and less dependence on CYP2D6. If no alternative exists, obtain baseline and follow-up ECGs and check potassium and magnesium.
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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References
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 Cobicistat
- Alfuzosin + Cobicistat Contraindicated
- Apalutamide + Cobicistat Contraindicated
- Cobicistat + Colchicine Contraindicated
- Cobicistat + Dronedarone Contraindicated
- Cobicistat + Eletriptan Contraindicated
- Cobicistat + Eplerenone Contraindicated
Frequently asked questions
Can I take Cobicistat with Thioridazine?
MediHelp rates the interaction as contraindicated. Cobicistat 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. Cobicistat strongly inhibits CYP3A and also inhibits CYP2D6, the main route of thioridazine clearance. Higher thioridazine concentrations can cause marked QTc prolongation, torsades de pointes and sudden death.
How serious is the interaction between Cobicistat 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 choose an antipsychotic with less QT risk and less dependence on CYP2D6. If no alternative exists, obtain baseline and follow-up ECGs and check potassium and magnesium.
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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