Amoxicillin and Birth Control
Amoxicillin is known to interact with a number of medications, and oral contraceptives are just one of them. Amoxicillin can make birth control pills less effective and you should therefore discuss with your healthcare provider the possible effects of the antibiotic to your birth control method.
Understanding the effects of amoxicillin on oral contraceptives is important to avoiding an unplanned pregnancy.
How does amoxicillin affect oral contraceptives?
Basically, antibiotics especially the tetracycline and penicillin category (which includes amoxicillin) impair the effectiveness of the pill. Although it is unclear how exactly amoxicillin affects oral contraceptives, there are two ways by which antibiotics are thought to reduce the effectiveness of birth control pills.
- Antibiotics such as Amoxicillin affect the action of liver enzymes which are necessary in the metabolism of estrogens. Since most birth control pills contain estrogen, they are metabolized at a much faster rate. The increased breakdown of birth control pills results in decreased estrogen levels as well as reduced effectiveness of the pills. This can eventually lead into unplanned pregnancy.
- Secondly, antibiotics reduce estrogens in the body by killing the bacteria that is necessary for re-circulating them. Once the pill is metabolized in the liver, it is secreted back into the intestine through the bile. Instead of being absorbed in the digestive tract, ‘good bacteria’ in the intestine converts estrogen back into its active form that can be used all over again. Birth control pills maintain constant estrogen levels in the blood through this cycle. Unfortunately, taking amoxicillin can bring this cycle to a halt, making oral contraceptives ineffective.
Both of these drug interactions can render birth control pills less effective, increasing the risks of an unplanned pregnancy. While early studies conducted some 15 years ago suggest interactions between birth control pills and antibiotics, more recent studies have shown inconclusive findings.
According to these recent studies, there has been no increased rate of pregnancy in patients taking oral contraceptives and antibiotics concurrently.
Nevertheless, there is a need for more up to date and better information. In the meantime, it is recommended that an additional method of birth control be used along with oral contraceptives while taking amoxicillin. As a matter of fact, drug manufacturers caution patients and healthcare providers of the possible effects of amoxicillin to birth control pills.
Remember that it is better to be safe than sorry. Therefore, if you are taking amoxicillin along with birth control pills, be sure to discuss with your healthcare provider the possible adjustment in the birth control methods. Some of the possible birth control methods include use of condom, diaphragm and spermicide. Talk with your doctor to find out which birth control technique is the best for you.