Some medications, including many antibiotics, may interact with birth control pills to cause serious health problems. They may affect the effectiveness of either the contraceptive or the interacting medication. The only antibiotic that is definitely known to have this effect is refampin, although this may also be true of other antibiotics.

Rifampin and Birth Control Pills

Rifampin is an antibiotic used most often in the treatment of tuberculosis, although it is also used for meningitis and some other infections. The antibiotic rifampin has been shown to reduce the amount of estradiol in the blood stream of some women. If a woman is using birth control pills, this reduces the effectiveness of the contraceptive effect of the birth control pill and increases the risk of pregnancy. If rifampin or any other antibiotic is prescribed while a woman is on birth control pills, she should use additional birth control protection measures while on the antibiotic that are not affected by it.

Other Hormonal Methods Affected by Antibiotics

The patch and several other methods of birth control could be affected by the use of antibiotics in this way. These include the ring, the sponge, and birth control shots as well as the patch, which are effective because they release the hormones into the woman's body and bloodstream. The risk of unwanted pregnancy is increased with the use of rifampin and possibly other antibiotics which could reduce the amount of the hormone released into the blood.

Use a Non-Hormonal Backup Method

A barrier method is advised to be used to supplement the regular hormonal birth control during the time an antibiotic is being taken. These will not be affected by the antibiotic. These include the diaphragm, male and female condoms, and the cervical cup. These are all physical barriers to conception and they are all more effective when a spermacidealgel is used with them. The female condom, the diaphragm, and the cervical cup are inserted by the woman in the woman into her vagina to cover the cervix, which is the opening to the uterus. This prevents sperm from entering the uterus and fertilizing the egg. This is accomplished without the use of hormones such as estradiol.

Use of a Condom

A condom should be used during intercourse anyway, even with the use of other contraceptives, because almost all of the birth control methods do not protect from sexually transmitted diseases, or STDs. The latex condom is the only way to protect from STDs besides total abstinence, and is easily affordable and available. Using a condom is especially important when a woman or her partner has intercourse with multiple partners, which increases the risk of STD.