Is it safe to have unprotected sex while taking antibiotics? What about if the antibiotics are for an STI? Do antibiotics reduce birth control effectiveness? Let’s walk through when it is — and isn't — time to think twice about having sex while taking antibiotics. 

Before we discuss each individual scenario, let’s make sure everyone’s on the same page about what exactly unprotected sex is. Unprotected sex includes vaginal, anal, and oral sex without a condom, which may increase your risk of contracting sexually transmitted infections (STIs) or unplanned pregnancies. You should always make sure you and your partner(s) test for STIs regularly. 

Antibiotics are used to treat, and in some cases prevent, bacterial infections. There’s many different types of and uses for antibiotics – several of which will be covered in this article. You may have been prescribed them for ear infections or strep throat as a kid, but they’re also commonly used to treat STIs, pneumonia, bronchitis, acne, and UTIs. 

Antibiotics and contraception 

You may have heard before that antibiotics can make your birth control pills less great at preventing pregnancy. But is this true for all antibiotics? The short answer is no; most antibiotics don’t affect the effectiveness of birth control. The keyword here is most — there are two types of antibiotics that may impact your birth control. 

1. Rifamycins: this group of antibiotics are used to treat infections such as tuberculosis and meningitis, or traveler’s diarrhea 
2. Doxycycline: this antibiotic is much more common than the first, often prescribed for STIs, rosacea, and other infections 

Ok, you’re taking a rifamycin or doxycycline — is sex out of the question? Nope! But because these antibiotics lessen the effectiveness of birth control pills, in order to prevent pregnancy you should consider using a contraceptive that isn’t impacted by your medicine. This includes (but not limited to) the external (penile) condom, internal (vaginal) condom, sponge, and diaphragm. 

It should be noted that while these two antibiotics can impact the effectiveness of hormonal birth control pills, it doesn’t impact other forms of contraceptives that you might assume would be similarly affected, such as IUDs, IUSs, and progesterone-only injections — all of which are ok on any antibiotic! 

Can I have sex if I'm taking antibiotics for an STI? 

To put it simply, throw the previous rules out the window if you’re taking antibiotics for a sexually transmitted infection, such as chlamydia or gonorrhea. How long after antibiotics can you have sex? For these infections, you should not have sex — unprotected or safe — until seven days after finishing the cycle of antibiotics prescribed, and until your partner has been treated and symptoms are gone. Even if you and your partner(s) are using a condom or other form of contraceptive that prevents STIs, you risk passing the infection back and forth. 

Following these guidelines can prevent unwanted pregnancy and the spread of STIs to you and your partner(s). Open communication with your partner and healthcare providers is key to responsible sexual health decisions, especially when antibiotics are in the picture.