Drug interactions
Ritonavir + Ulipristal
Severity: Moderate
Ritonavir and Ulipristal: 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 and is expected to increase ulipristal exposure substantially. The consequences of higher exposure are not well established.
What this interaction means in plain words
Ritonavir and Ulipristal 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.
Why it happens
Strong CYP3A4 inhibition by ritonavir reduces ulipristal metabolism.
What to do
Prefer a copper IUD or an alternative emergency contraceptive. If ulipristal is used, counsel on adverse effects.
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 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 Ritonavir with Ulipristal?
MediHelp rates the interaction as moderate. Ritonavir and Ulipristal 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 and is expected to increase ulipristal exposure substantially. The consequences of higher exposure are not well established.
How serious is the interaction between Ritonavir and Ulipristal?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Prefer a copper IUD or an alternative emergency contraceptive. If ulipristal is used, counsel on adverse effects.
What other medicines interact with Ritonavir?
MediHelp also lists interactions of Ritonavir with, for example, Alfuzosin, Amiodarone, Avanafil. The full list is on the Ritonavir page.
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