Drug interactions
Desogestrel-ethinyl estradiol + Fosamprenavir
Severity: Major
Desogestrel-ethinyl estradiol and Fosamprenavir: major 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
Fosamprenavir (given with or without ritonavir) can change the circulating levels of ethinyl estradiol and the progestin, and may lower amprenavir exposure. The contraceptive may therefore be less reliable, and the antiretroviral response may also be affected.
What this interaction means in plain words
Desogestrel-ethinyl estradiol and Fosamprenavir 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.
Why it happens
Altered metabolism of estrogen and progestin through combined CYP3A inhibition and induction effects of the protease inhibitor regimen, with a reciprocal drop in amprenavir exposure.
What to do
Advise a non-hormonal or alternative contraceptive method such as a copper IUD or condoms instead of relying on the combined pill. Monitor HIV viral load if the combination is continued.
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 Desogestrel-ethinyl estradiol and Fosamprenavir, 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.
Other interactions of Desogestrel-ethinyl estradiol
- Desogestrel-ethinyl estradiol + Fezolinetant Contraindicated
- Aminocaproic acid + Desogestrel-ethinyl estradiol Major
- Amobarbital + Desogestrel-ethinyl estradiol Major
- Anastrozole + Desogestrel-ethinyl estradiol Major
- Apalutamide + Desogestrel-ethinyl estradiol Major
- Atazanavir + Desogestrel-ethinyl estradiol Major
Frequently asked questions
Can I take Desogestrel-ethinyl estradiol with Fosamprenavir?
MediHelp rates the interaction as major. Desogestrel-ethinyl estradiol and Fosamprenavir 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. Fosamprenavir (given with or without ritonavir) can change the circulating levels of ethinyl estradiol and the progestin, and may lower amprenavir exposure. The contraceptive may therefore be less reliable, and the antiretroviral response may also be affected.
How serious is the interaction between Desogestrel-ethinyl estradiol and Fosamprenavir?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Advise a non-hormonal or alternative contraceptive method such as a copper IUD or condoms instead of relying on the combined pill. Monitor HIV viral load if the combination is continued.
What other medicines interact with Desogestrel-ethinyl estradiol?
MediHelp also lists interactions of Desogestrel-ethinyl estradiol with, for example, Fezolinetant, Aminocaproic acid, Amobarbital. The full list is on the Desogestrel-ethinyl estradiol 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.
