Drug interactions
Atazanavir + Ulipristal
Severity: Moderate
Atazanavir 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
Atazanavir inhibits CYP3A4 and can raise ulipristal concentrations. Higher exposure may increase adverse effects of ulipristal, and the safety of increased exposure is not well established. Ritonavir- or cobicistat-boosted regimens would be expected to have a greater effect.
What this interaction means in plain words
Atazanavir 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
Inhibition of CYP3A4-mediated metabolism of ulipristal by atazanavir.
What to do
Counsel the patient about possible increased adverse effects and consider an alternative emergency contraceptive such as a copper IUD or levonorgestrel with appropriate dosing. Avoid repeated ulipristal dosing within the same cycle.
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 Atazanavir
- Alfuzosin + Atazanavir Contraindicated
- Atazanavir + Avanafil Contraindicated
- Atazanavir + Dronedarone Contraindicated
- Atazanavir + Eletriptan Contraindicated
- Atazanavir + Eplerenone Contraindicated
- Atazanavir + Ergotamine Contraindicated
Frequently asked questions
Can I take Atazanavir with Ulipristal?
MediHelp rates the interaction as moderate. Atazanavir 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. Atazanavir inhibits CYP3A4 and can raise ulipristal concentrations. Higher exposure may increase adverse effects of ulipristal, and the safety of increased exposure is not well established. Ritonavir- or cobicistat-boosted regimens would be expected to have a greater effect.
How serious is the interaction between Atazanavir 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: Counsel the patient about possible increased adverse effects and consider an alternative emergency contraceptive such as a copper IUD or levonorgestrel with appropriate dosing. Avoid repeated ulipristal dosing within the same cycle.
What other medicines interact with Atazanavir?
MediHelp also lists interactions of Atazanavir with, for example, Alfuzosin, Avanafil, Dronedarone. The full list is on the Atazanavir page.
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