Q: I heard that antibiotics interfere with birth control pills, but I’m on the birth control that gets implanted under my skin – will antibiotics interfere with that too?
A: I’m so glad you asked this question! This is one of the biggest medical myths of all time; one that gets propagated in doctors’ offices, health clinics, hospitals, blogs, magazines – and OK fine, student health centers – every day. So now, for the first time ever… in print… online… on this blog… the TRUTH!
The only antibiotic that has ever been shown to interfere with birth control levels and effectiveness is a medicine called rifampin which is used to treat tuberculosis. Rifampin may also interfere with the birth control patch and vaginal ring so if you are taking it, be sure to use a back-up, non-hormonal (i.e. condom) form of birth control.
There are some other medications that can interfere with your birth control, however, and if you are taking any of them you should always use back-up contraception.
- Phenytoin (Dilantin)
- Carbamazepine (Tegretol)
- Topirimate (Topamax)
- St. John’s Wort (herbal supplement)
But in general, your birth control will not be affected by any run-of-the-mill antibiotic that you might be taking for things like sinus infections, strep throat, urinary tract infections, skin infections, acne, etc. Some people believe that because antibiotics disrupt the normal bacteria in the gastrointestinal tract, they will interfere with the absorption of the birth control pills from your stomach. But this is not an issue, and even if it were, it wouldn’t apply to birth control methods that don’t involve swallowing pills like the skin patch or the vaginal ring or Implanon.
Now, there are enough women out there who swear that they have little antibiotic babies running around the house that your health care provider will probably still tell you to use back-up just in case. And birth control doesn’t do anything to protect you against sexually transmitted infections, so using a condom is a good idea no matter what medications you’re taking. But you can rest assured that your birth control is just as effective when you’re taking antibiotics as when you’re not.
John A. Vaughn, MD (OSU SHS)