The pill and antibiotics

In most cases, taking antibiotics won’t make the pill less effective. However, there are two types of antibiotics which do negatively affect the contraceptive pill: Rifampin and Rifabutin. These medicines treat tuberculosis and meningitis and make the contraceptive method less effective. So, if you are receiving treatment for either of these illnesses, you should use additional contraception alongside the pill.

Why do Rifampin and Rifabutin affect the pill?

Both Rifampin and Rifabutin are what are known as ‘enzyme-inducing’ medicines. This means they increase the level of certain enzymes in the body to increase the speed at which they work. This increased enzyme level affects the hormones in the pill that prevents pregnancy. As these hormones are broken down faster before they get a chance to work properly, it makes them less effective than advertised.

What should I do if I’m prescribed Rifampin or Rifabutin?

If you rely on the pill as a contraception method and you’ve been prescribed either of these antibiotics to treat an illness, then you’ll need to look into using additional types of contraception during this time. You can keep taking the pill as per usual to keep your cycle regular, but using condoms or a diaphragm until you come off the antibiotic will ensure the chances of pregnancy is low.

Does Rifampin and Rifabutin affect other types of contraception?

There are other types of hormonal contraceptives which are also rendered less effective by taking Rifampin and Rifabutin antibiotics. These are:

The vaginal ring
The contraceptive patch
The combined pill (progestin and oestrogen)
The mini pill (progestin only)
The contraceptive implant

This also means that these forms of hormonal contraceptives are not a suitable alternative contraception method when taking Rifampin and Rifabutin.

Which contraceptives are safe to use while taking Rifampin and Rifabutin?

The following methods of contraception are not affected by these antibiotics:

IUD (copper coil)
IUS (hormonal coil)
Contraceptive injection
Condoms (male and female condoms)
Diaphragm

These forms of contraception are suitable as an alternative or additional contraceptive method to protect against pregnancy while taking Rifampin or Rifabutin.

Will other antibiotics affect the pill?

If you’re taking any other antibiotic that isn’t Rifampin or Rifabutin, it will not interfere with the contraceptive pill and its effectiveness. Common types of antibiotics include:

Amoxicillin
Doxycycline
Cephalexin
Metronidazole
Clindamycin
Ciprofloxacin
Azithromycin

However, taking antibiotics can cause vomiting or an upset stomach. If this happens, you may not be protected against pregnancy if you’re on the pill. In this situation, you should use condoms until the symptoms resolve, and you start feeling better for seven days.