Drug interactions
Diazepam + Ritonavir
Severity: Major
Diazepam and Ritonavir: major 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
Ritonavir strongly inhibits CYP3A4 and also CYP2C19, which can markedly raise diazepam and desmethyldiazepam exposure. This may cause excessive sedation and respiratory depression, and the effect is prolonged because of diazepam's long half-life.
What this interaction means in plain words
Diazepam and Ritonavir 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.
Diazepam belongs to Musculoskeletal; Ritonavir belongs to Anti Virals.
Why it happens
Ritonavir inhibits CYP3A4 and CYP2C19 mediated metabolism of diazepam.
What to do
Avoid the combination where possible and choose a benzodiazepine less dependent on oxidative metabolism, such as lorazepam. If it is unavoidable, use the lowest diazepam dose and monitor for oversedation and respiratory depression.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Diazepam and Ritonavir, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
References
Other interactions of Diazepam
Other interactions of Ritonavir
- Alfuzosin + Ritonavir Contraindicated
- Amiodarone + Ritonavir Contraindicated
- Avanafil + Ritonavir Contraindicated
- Colchicine + Ritonavir Contraindicated
- Dronedarone + Ritonavir Contraindicated
- Eletriptan + Ritonavir Contraindicated
Frequently asked questions
Can I take Diazepam with Ritonavir?
MediHelp rates the interaction as major. Diazepam and Ritonavir 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 strongly inhibits CYP3A4 and also CYP2C19, which can markedly raise diazepam and desmethyldiazepam exposure. This may cause excessive sedation and respiratory depression, and the effect is prolonged because of diazepam's long half-life.
How serious is the interaction between Diazepam and Ritonavir?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible and choose a benzodiazepine less dependent on oxidative metabolism, such as lorazepam. If it is unavoidable, use the lowest diazepam dose and monitor for oversedation and respiratory depression.
What other medicines interact with Diazepam?
MediHelp also lists interactions of Diazepam with, for example, Calcium / magnesium / potassium / sodium oxybates, Alfentanil, Alprazolam. The full list is on the Diazepam page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
