Oral Contraceptives

Everyday you take protease inhibitors. They keep your viral load down and your CD4 count as high as possible. You take the pills right on time, just like the doctor told you to. Everyday you take a birth control pill to keep from getting pregnant, reduce your painful periods or regulate your cycle. Your viral load is low and you haven’t gotten pregnant, so everything is fine, right? Maybe.

In the past few years there have been lots of new drugs for HIV. The newest drugs are protease inhibitors, and more people are taking them because they fight HIV successfully. However, we do not know what effect protease inhibitors have on birth control pills. What research has been done is not widely published. In addition, with so many anti HIV drugs around, a woman is bound to become confused.

What we do know is that some protease inhibitors make your birth control pills less effective. This depends on which drugs you are taking. If you are taking Norvir (ritonavir) or Viracept (nelfinavir), the amount of birth control in your system may be lowered. This causes the birth control to be less effective. In one study, women who took birth control pills were given ritonavir. After they took ritonavir the amount of birth control in their blood was 40% lower than it should have been. Nelfinavir also reduces the level of contraceptive in a woman’s body by anywhere from 18% - 47%. Invirase (saquinavir) and Crixivan (indinavir) have not shown any effect on birth control pills. However, they have also not been studied very much.

So why do these drugs act this way? Birth control pills are made up of a man-made form of hormones that are naturally found in a woman's body. Hormones are the chemicals in your body that make you get your period. There needs to be the right amount of these hormones in your system so that you won't get pregnant, will get your period on time, and have less painful cramps. These hormones are metabolized, or “broken down”, gradually by the body throughout the day and after twenty-four hours they need to be replaced. That’s when you take another birth control pill. When you start taking a protease inhibitor your metabolism is sped up. Therefore, the hormones are “broken down” faster, and there are less of them in your system than you need. Since some protease inhibitors speed up your metabolism to up to twice as fast, you have less birth control in your system by the end of the day. This can lead to you being at up to twice as likely to get pregnant, have an irregular period, or experience painful cramping.

Hopefully, we will soon have more information about the effects that protease inhibitors have on birth control pills. Roxane Laboratory is currently enrolling HIV positive women in New York City and San Francisco to study the effects of protease inhibitors on the birth control pill. Here in Seattle, the University of Washington’s AIDS Clinical Trails Unit is looking for women to participate in a study on the effects of an AZT/Crixivan (indinavir) combination on oral and injectable contraceptives. If you are interested in participating in this study, contact the screening nurse, Karen Novak, at (206)731-0206.

The bottom line is that if you are taking both one of the protease inhibitors and birth control pills you should talk with your provider. You may want to increase your birth control dosage and/or talk about other ways of preventing pregnancy, reducing cramping or regulating your period. A common sense caution, however: birth control pills should never be increased or “doubled up” unless under the supervision of your provider. Doing so can be dangerous to your health. If you are wondering what other drugs might effect your birth control, consult the package insert of both drugs, and then talk to your provider about your options.

This is a Non-Profit Organization You can follow this link to find out more on donations: