Drug interactions
Ethinyl estradiol-drospirenone + Fosamprenavir
Severity: Major
Ethinyl estradiol-drospirenone 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, particularly with ritonavir, alters ethinyl estradiol and progestin exposure, and hormonal contraceptives may reduce amprenavir levels. This risks contraceptive failure and loss of virologic response.
What this interaction means in plain words
Ethinyl estradiol-drospirenone 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
Mixed CYP3A4 inhibition and induction/glucuronidation effects alter hormone and amprenavir concentrations.
What to do
Use non-hormonal contraception rather than this combined pill. Monitor HIV viral load if hormonal therapy is used.
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?
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Other interactions of Ethinyl estradiol-drospirenone
- Ethinyl estradiol-drospirenone + Fezolinetant Contraindicated
- Ethinyl estradiol-drospirenone + Ombitasvir / paritaprevir / ritonavir Contraindicated
- Ethinyl estradiol-drospirenone + Ombitasvir / paritaprevir / ritonavir and dasabuvir Contraindicated
- Ethinyl estradiol-drospirenone + Tranexamic acid Contraindicated
- Aminocaproic acid + Ethinyl estradiol-drospirenone Major
- Amobarbital + Ethinyl estradiol-drospirenone Major
Frequently asked questions
Can I take Ethinyl estradiol-drospirenone with Fosamprenavir?
MediHelp rates the interaction as major. Ethinyl estradiol-drospirenone 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, particularly with ritonavir, alters ethinyl estradiol and progestin exposure, and hormonal contraceptives may reduce amprenavir levels. This risks contraceptive failure and loss of virologic response.
How serious is the interaction between Ethinyl estradiol-drospirenone 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: Use non-hormonal contraception rather than this combined pill. Monitor HIV viral load if hormonal therapy is used.
What other medicines interact with Ethinyl estradiol-drospirenone?
MediHelp also lists interactions of Ethinyl estradiol-drospirenone with, for example, Fezolinetant, Ombitasvir / paritaprevir / ritonavir, Ombitasvir / paritaprevir / ritonavir and dasabuvir. The full list is on the Ethinyl estradiol-drospirenone page.
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