What the FDA labels say about taking them together
Efavirenz and etonogestrel
Efavirenz's FDA label of March 31, 2024 names etonogestrel in its drug interactions section, and etonogestrel's label names efavirenz too. The efavirenz label: “… should be used in addition to hormonal contraceptives. Decreased exposure of etonogestrel may be expected. There have been postmarketing reports of contraceptive failure with etonogestrel in efavirenz-exposed patients.”
Check it at the source: the efavirenz FDA label on DailyMed (effective March 31, 2024, Cipla USA Inc.); the etonogestrel FDA label on DailyMed (effective May 28, 2026, Organon LLC).
What does the efavirenz label say about etonogestrel?
Efavirenz label, drug interactionsConcomitant Drug Class/Drug Name: Hormonal contraceptives: Oral Ethinyl estradiol/ Norgsetimate Implant Etonogestrel; Effect: ↑ active metabolites of norgestimate * ↓ etonogestrel; Clinical Comment: 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. Decreased exposure of etonogestrel may be expected. There have been postmarketing reports of contraceptive failure with etonogestrel in efavirenz-exposed patients.
Source: FDA drug label (Efavirenz), Cipla USA Inc., effective March 31, 2024 (SPL set 92603fa5-7a2c-4bfb-9a70-aadb4fba952c), via openFDA; the full label on DailyMed
What does the etonogestrel label say about efavirenz?
Etonogestrel label, drug interactionsSome drugs or herbal products that may decrease the effectiveness of HCs include efavirenz, phenytoin, barbiturates, carbamazepine, bosentan, felbamate, griseofulvin, oxcarbazepine, rifampicin, topiramate, rifabutin, rufinamide, aprepitant, and products containing St. John's wort.
Source: FDA drug label (Nexplanon), Organon LLC, effective May 28, 2026 (SPL set 487f8a62-e142-457c-97cc-2e398fde7594), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Efavirenz | Etonogestrel | |
|---|---|---|
| Labeled for | HIV | Birth control |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $1.28 per tablet 600 mg tablet | n/a |
| Shortage now | No current entry | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once