Efavirenz and Estradiol and dienogest interaction
Efavirenz and Estradiol and dienogest: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Estradiol and dienogest (Natazia) label · effective 2024-06-26
Women who take medications that are strong CYP3A4 inducers should not choose Natazia as their oral contraceptive while using these inducers and for at least 28 days after discontinuation of these inducers due to the possibility of increased breakthrough bleeding and/or decreased contraceptive efficacy.
…exposure at steady state. [See Clinical Pharmacology (12.3).] Substances Increasing the Systemic Exposure of COCs (enzyme inhibitors): Concomitant administration of moderate or strong CYP3A4 inhibitors like azole antifungals (for example, ketoconazole, itraconazole, voriconazole, fluconazole), verapamil, macrolides (for example, clarithromycin, erythromycin), diltiazem,…
In a multiple dose study investigating the effect of CYP3A4 inhibitors (ketoconazole and erythromycin) on Natazia, steady state estradiol and dienogest exposures were increased when co-administered with ketoconazole or erythromycin [see Clinical Pharmacology ( 12.3 )] .
• CYP3A4 induction : Women taking strong CYP3A4 inducers (for example, carbamazepine, phenytoin, rifampicin, and St.
Drug Interactions Women who take medications that are strong cytochrome P450 3A4 (CYP3A4) inducers (for example, carbamazepine, phenytoin, rifampicin, and St.
From the Efavirenz label · effective 2024-03-31
Hormonal contraceptives: Oral Ethinyl estradiol/ Norgsetimate Implant Etonogestrel ↑ active metabolites of norgestimate * ↓ etonogestrel A reliable method of barrier contraception should be used in addition to hormonal contraceptives.
A reliable method of barrier contraception should be used in addition to hormonal contraceptives.
There have been postmarketing reports of contraceptive failure with etonogestrel in efavirenz-exposed patients.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.