Drug interactions
Nirmatrelvir / ritonavir + Quetiapine
Severity: Major
Nirmatrelvir / ritonavir and Quetiapine: 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
Ritonavir-boosted nirmatrelvir is a strong CYP3A4 inhibitor and can greatly increase quetiapine concentrations. This raises the risk of marked sedation, hypotension, and QT prolongation.
What this interaction means in plain words
Nirmatrelvir / ritonavir and Quetiapine 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.
Why it happens
Strong CYP3A4 inhibition by ritonavir reduces quetiapine clearance.
What to do
Reduce quetiapine to about one sixth of the usual dose during treatment, or temporarily hold it, and monitor for sedation, hypotension and QTc. Return to the previous dose after the CYP3A4 inhibition wears off, which may take several days after the last 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 Quetiapine
- Adagrasib + Quetiapine Major
- Amiodarone + Quetiapine Major
- Amisulpride + Quetiapine Major
- Amoxapine + Quetiapine Major
- Anagrelide + Quetiapine Major
- Apalutamide + Quetiapine Major
Frequently asked questions
Can I take Nirmatrelvir / ritonavir with Quetiapine?
MediHelp rates the interaction as major. Nirmatrelvir / ritonavir and Quetiapine 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. Ritonavir-boosted nirmatrelvir is a strong CYP3A4 inhibitor and can greatly increase quetiapine concentrations. This raises the risk of marked sedation, hypotension, and QT prolongation.
How serious is the interaction between Nirmatrelvir / ritonavir and Quetiapine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Reduce quetiapine to about one sixth of the usual dose during treatment, or temporarily hold it, and monitor for sedation, hypotension and QTc. Return to the previous dose after the CYP3A4 inhibition wears off, which may take several days after the last dose.
What other medicines interact with Quetiapine?
MediHelp also lists interactions of Quetiapine with, for example, Adagrasib, Amiodarone, Amisulpride. The full list is on the Quetiapine page.
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