Dear Doctor,
I have a question about my birth control and antibiotics. I’ve been on oral contraceptives for a couple of years now with no issues, but I was recently prescribed antibiotics I’m worried.
I’ve heard that antibiotics can make birth control less effective, and I’m concerned about the risk of an unintended pregnancy. Is this something I should actually be worried about—or am I being dramatic? Are there specific antibiotics that interfere with birth control? And what should I do to stay protected while I’m on this medication?
Thanks so much for your help!
Best,
Better Safe Than Sorry
Hello, Better Safe Than Sorry,
You’re not being dramatic—we hear this question often, and it’s a valid concern.
The short answer is that most antibiotics do not reduce the effectiveness of hormonal birth control. The idea that all antibiotics cancel out birth control is a common myth.
The longer answer is that there are a few specific, less commonly prescribed antibiotics that can interfere with hormonal contraception. The most well-known example is rifampin, an antibiotic used to treat tuberculosis and a small number of other infections. Rifampin is an enzyme-inducing medication, meaning it speeds up how your liver processes hormones. This can lower hormone levels from birth control pills, patches, or rings—making them less effective and increasing the risk of pregnancy, even when used correctly.
Aside from rifampin, most broad-spectrum antibiotics (like amoxicillin or doxycycline) have not been shown to make birth control less effective.
Aside from antibiotics, some other medications can reduce the efficacy of hormonal birth control, such as certain anti-fungal medications, anti-seizure drugs, and some medications that treat HIV. That is why reviewing new prescriptions with your pharmacist and making sure your healthcare providers are aware of medications prescribed by other specialists is important. You never know how something might interact in your system, and it’s always better to err on the side of caution.
The other thing to consider is what type of birth control you are using. When we talk about birth control, people tend to think of the pill, which enters your bloodstream through absorption by your stomach. But other forms of birth control, such as the arm implant, patch or IUD, deliver the medication differently, so it really won’t be affected by antibiotics at all.
While we’re confident that only a small number of antibiotics interfere with birth control, it isn’t possible to study every medication combination. For extra peace of mind, using a backup method of birth control, such as condoms or a diaphragm, is a smart option. If recommended, start backup contraception on the first day of antibiotics and continue for 7–14 days after finishing the medication, depending on your provider’s guidance.
Always check with your healthcare provider before making changes to your contraception or medications. Being cautious with your reproductive health is never a bad thing.
If you have additional questions or concerns, please contact your Genesis OB/GYN provider to schedule an appointment.
If you have further questions or concerns, contact your Genesis OB/GYN provider and request an appointment today.
Best,
Dr. Erin Sperry Schlueter
Erin Sperry Schlueter, MD, FACOG, is a board-certified OB/GYN practicing at Pueblo OB/GYN in Tucson and South Tucson. She specializes in normal and high-risk pregnancies, the management of abnormal uterine bleeding, and adolescent gynecology.
