Carbamazepine and Norethindrone and ethinyl estradiol interaction
Carbamazepine and Norethindrone and ethinyl estradiol: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Norethindrone and ethinyl estradiol (Lo Loestrin Fe) label · effective 2025-03-07
Counsel patients to use a back-up method or alternative method of contraception when enzyme inducers are used with COCs ( 7.1 ) -- - ---------- ------ USE IN SPECIFIC POPULATIONS---- -- -- --------- ---- Lactation: Not recommended; Lo Loestrin Fe can decrease milk production ( 8.2 )
Some drugs or herbal products that may decrease the effectiveness of hormonal contraceptives include: barbiturates bosentan carbamazepine felbamate griseofulvin oxcarbazepine phenytoin rifampin St.
From the Carbamazepine (EQUETRO) label · effective 2025-08-19
EQUETRO can reduce the effectiveness of hormonal contraceptives.
Equetro may decrease the effectiveness of hormonal contraceptives.
EQUETRO decreases the concentrations of the following drugs through induction of their metabolism: Hormonal Contraceptives (CYP3A4 Substrates) EQUETRO is a strong inducer of CYP3A4.
EQUETRO can increase the metabolism of certain hormonal contraceptives (through CYP3A4 induction) such as oral and subdermal implant contraceptives, leading to significantly lower plasma concentrations of hormones.
This can cause contraceptive failure or breakthrough bleeding.
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.