A: The vast majority of antibiotics have no impact on the efficacy of birth control.
Note: “The bottom line?” paragraph edited on 12/13/22.
The medication guides that come with all medications in the U.S. warn patients that antibiotics (if anyone reads these?!) may interact with your birth control. In most cases, they are talking about hormonal contraception like the combined birth control pill (ethinyl estradiol and progestin), the progestin-only pill, an implant, a patch, or a vaginal ring.
In reality, most antibiotics do not interact with these birth control methods. Common antibiotics we might take for most infections, such as penicillin and azithromycin, do not interact. It is true, however, that some antibiotics interact with birth control, mainly rifampin-like antibiotics, which are primarily used to treat tuberculosis and meningitis.
Why? 🤓Nerd Alert! 🤓 Rifampin produces enzymes in your liver that break estrogen down faster than normal. Rifampin-like antibiotics thus lower levels of birth control hormones (ethinyl estradiol and progestin) in women taking hormonal contraceptives.
The bottom line? Most hormonal birth control still works well if you take antibiotics. If you need to take a rifampin-like antibiotic, you should consider either a backup method such as condoms or switching to an IUD.
There are other medications that interact with hormonal birth control, of course, such as anti-seizure drugs like topiramate (Topamax – also often used for migraine) and phenobarbital and anti-sleepiness drug modafinil (Provigil) and armodafinil (Nuvigil). Always ask your clinician or pharmacist if you’re not sure!!
Those Nerdy Girls