The combined contraceptive pill (the pill) can interact with other medicines. Some of the more common interactions are listed below. However, this is not a complete list.
If you want to check that your medicines are safe to take with the pill, ask your doctor or pharmacist, or read the patient information leaflet that comes with your medicine.
Antibiotics
The following antibiotics reduce the effectiveness of the pill:
Rifampicin is used to treat conditions such as tuberculosis, and can be prescribed for several months at a time. The antibiotics prescribed for some common conditions, such as acne, do not usually affect the contraceptive pill, but ask your GP if you are unsure.
Long-term rifampicin or rifabutin
If you are going to be taking rifampicin or rifabutin for over two months, you may want to consider starting or changing to a contraception method that is not affected by these medicines. For example:
Short-term rifampicin or rifabutin
If you are taking rifampicin or rifabutin for less than two months and want to continue with your same combined contraceptive pill, you must discuss this with your doctor or specialist nurse. They will be able to get detailed up-to-date guidance from the Faculty of Sexual and Reproductive Healthcare.
You may need to use additional contraception (such as condoms) while you are taking the antibiotics and for 28 days after finishing the course. You may also need to change to a higher strength pill and take your pill in a different way from usual. You will need to continue this for 28 days after finishing the course.
Your GP will be able to give you further advice.
Other medicines
The pill can interact with medicines called enzyme inducers, which reduce the effectiveness of the pill.
Examples of enzyme enducers include:
- the epilepsy drugs carbamazepine, oxcarbazepine, phenytoin, phenobarbital, primidone and topiramate
- St John’s Wort (a herbal remedy)
- antiretroviral medicines used to treat HIV
Your GP or nurse may advise you to use an alternative or additional form of contraception while you are taking one of these medicines.
