Drug interactions
Ketamine + Ritonavir
Severity: Moderate
Ketamine and Ritonavir: moderate 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 is a strong CYP3A4 inhibitor, so it would be expected to raise rather than lower ketamine concentrations. Higher exposure may prolong sedation, dissociation and cardiovascular effects, especially with oral or repeated dosing. With long-term use ritonavir also has some inducing activity, so the net effect can vary.
What this interaction means in plain words
Ketamine and Ritonavir can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Ketamine belongs to Central Nervous System; Ritonavir belongs to Anti Virals.
Why it happens
Ritonavir inhibits CYP3A4-mediated ketamine N-demethylation, potentially increasing ketamine exposure.
What to do
Titrate ketamine to effect with reduced initial doses and monitor sedation, blood pressure and recovery time. Be alert to prolonged effects after oral dosing.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Ketamine
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 Ketamine with Ritonavir?
MediHelp rates the interaction as moderate. Ketamine and Ritonavir can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Ritonavir is a strong CYP3A4 inhibitor, so it would be expected to raise rather than lower ketamine concentrations. Higher exposure may prolong sedation, dissociation and cardiovascular effects, especially with oral or repeated dosing. With long-term use ritonavir also has some inducing activity, so the net effect can vary.
How serious is the interaction between Ketamine and Ritonavir?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Titrate ketamine to effect with reduced initial doses and monitor sedation, blood pressure and recovery time. Be alert to prolonged effects after oral dosing.
What other medicines interact with Ketamine?
MediHelp also lists interactions of Ketamine with, for example, Benzhydrocodone / acetaminophen, Brexanolone, Buprenorphine buccal. The full list is on the Ketamine page.
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