Drug interactions
Clozapine + Darunavir
Severity: Major
Clozapine and Darunavir: major interaction.
Last updated Sources: UK SmPC
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
Darunavir, usually boosted with ritonavir or cobicistat, inhibits CYP3A4 and may raise clozapine concentrations. Ritonavir also induces CYP1A2, so the net effect is unpredictable and toxicity or loss of effect could occur.
What this interaction means in plain words
Clozapine and Darunavir 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.
Clozapine belongs to Central Nervous System; Darunavir belongs to Anti Virals.
Why it happens
CYP3A4 inhibition by the boosted protease inhibitor, with possible opposing CYP1A2 induction by ritonavir.
What to do
Monitor clozapine levels and clinical response when starting or stopping the antiretroviral and adjust the dose accordingly. Watch for sedation, hypotension, seizures and QT prolongation.
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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References
- Clozapine Viatris 100 mg Orodispersible Tablets - SmPC sections 4.3/4.5 (class statement: protease inhibitors; "pharmacokinetic interactions with CYP 3A4 inhibitors such as azole antimycotics, cimetidine, erythromycin and protease inhibitors are unlikely, although some ha") — electronic medicines compendium (UK SmPC)
Other interactions of Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Other interactions of Darunavir
- Alfuzosin + Darunavir Contraindicated
- Avanafil + Darunavir Contraindicated
- Darunavir + Dronedarone Contraindicated
- Darunavir + Eletriptan Contraindicated
- Darunavir + Ergotamine Contraindicated
- Darunavir + Flibanserin Contraindicated
Frequently asked questions
Can I take Clozapine with Darunavir?
MediHelp rates the interaction as major. Clozapine and Darunavir 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. Darunavir, usually boosted with ritonavir or cobicistat, inhibits CYP3A4 and may raise clozapine concentrations. Ritonavir also induces CYP1A2, so the net effect is unpredictable and toxicity or loss of effect could occur.
How serious is the interaction between Clozapine and Darunavir?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor clozapine levels and clinical response when starting or stopping the antiretroviral and adjust the dose accordingly. Watch for sedation, hypotension, seizures and QT prolongation.
What other medicines interact with Clozapine?
MediHelp also lists interactions of Clozapine with, for example, Deferiprone, Irinotecan, Pimozide. The full list is on the Clozapine page.
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