Most antibiotics don't affect contraception. It's now thought that the only types of antibiotic that interact with hormonal contraception and make it less effective are rifampicin-like antibiotics.
These can be used to treat or prevent diseases, including tuberculosis and meningitis. They include:
These types of antibiotics can increase the enzymes in your body. This is known as being "enzyme-inducing", and can affect hormonal contraception.
If you are taking enzyme-inducing antibiotics while using hormonal contraception, to avoid getting pregnant you'll need to use additional contraception, such as condoms, change to a different method of contraception, or take your contraception in a different way.
Apart from those mentioned above, all other antibiotics are not enzyme-inducing. However, the patient information leaflet that comes with other types of antibiotics may say they could affect your contraception. This information may be different from evidence-based guidelines used by health professionals.
Find out about other medicines which may affect contraception.
Additional contraception when taking antibiotics
If you're going to take rifampicin or rifabutin for more than two months, you may want to consider starting, or changing to, a contraception method that's not affected by these medicines.
You should consider doing this if you're currently using:
Contraception methods that aren't affected by rifampicin or rifabutin include:
If you're taking rifampicin or rifabutin for less than two months and want to continue using the same hormonal contraception, you must discuss this with your doctor. You may be asked to take this contraception in a different way from usual and use condoms as well. You will need to continue this for 28 days after finishing the antibiotics.
One option for women who have a contraceptive implant and need to take a short dose of rifampicin (for preventing meningitis, for example) is a single dose of the progestogen injection. The implant can stay in place while you're covered by the injection.
You and your doctor can get up-to-date guidance about contraception and antibiotics from the Faculty of Sexual and Reproductive Healthcare.
You don't normally need to use additional contraception if you're taking antibiotics other than rifampicin and rifabutin.
However, if the antibiotics or the illness they are treating cause diarrhoea or vomiting, absorption of the contraceptive pill may be affected. For more information, see What if I'm on the pill and I'm sick or have diarrhoea?
Your health, your choices