Question
Does efavirenz interact with dydrogesterone for menopause?
11 July 2026. Related: All topics, Drug interactions.
I’m 42 years old and lately I m on Atripla and in premenopause too. The gynechologist perscribed the hormone dydrogesterone for 5 days.
Is Atripla lnown to cause menstrual cycle loss?
I have read that efavirenz in Atripla has no goodinteraction between them. How many hours between should I take hormones and Atripla?
Answer
Hi there
Thanks for your Q and for letting us answer this online.
The Liverpool Drug Interaction website says:
“Co-administration is predicted to decrease dydrogesterone exposure. In addition, exposure of estrogens/estradiol administered as part of HRT may also decrease. Monitor for signs of hormone deficiency.”
This means that your doctor should really check your levels of this hormone.
As this is only for five days though, is your doctor going to do this.
Otherwise, perhaps switching to a different HIV combination or adjusting the hormone dose might overcome the interaction.
HIV combinations that include dolutegravir instead of efavirenz will not have this problem. Most people find dolutegravir and easier drug to take, if this is available in your country.
Hi Pablo – please see this link for info on PEP, including Q10:
https://i-base.info/qa/factsheets/pep-faq#How-long-do-you-need-to-take-PEP-for
Today is my last day of PEP.
However, I’ve been taking a 175 mg echinacea pill every day, usually 6–10 hours after my PEP dose.
I only found out today that it might not be recommended to take echinacea while on PEP.
Do you think I should continue taking PEP for another month to make sure it has been effective?
I’d really appreciate it if you could reply as soon as possible. Thank you!