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Dr. Jim Shelton's Pearls "Pearl" for the week of March 26, 2004

ARVs and OC Effectiveness

I believe you have made a very strong case that women on anti-retrovirals (ARVs) should have good access to safe and effective contraception. But I have heard some ARVs may reduce the effectiveness of oral contraceptives (OCs). What do you recommend?

The potential for ARVs to lower the effectiveness of OCs varies from ARV to ARV, and data are quite limited. Importantly, the commonly used non-nucleoside reverse transcriptase inhibitor (NNRTI), Nevirapine, speeds up liver metabolism of contraceptive hormones. As a result, the contraceptive blood level is reduced by as much as one
third. Paradoxically, the other major NNRTI, Efavirenz, may variably either increase or decrease liver metabolism.*

How important is such a reduction in hormone blood levels of up to one third? It is hard to say without more data. Importantly, in developing countries, OCs almost always contain 30 to 35 mcg of estrogen. Yet in the U.S. and Europe, ultra-low-dose 20 mcg OCs are approved, widely used, and highly effective if taken every day.

In view of all this, WHO has categorized taking of OCs in the context of ARVs as Category 2 ("Generally use the method, though some special care may be needed") with an asterisk referring to a table on hormone/ARV interactions.

OCs would not be my first choice for contraception for a woman on an ARV with effects similar to Neviripine. However, if OCs are a woman's first choice, I believe it can be reasonable to provide 30-35 mcg estrogen OCs, if the provider believes she will take them every day (after all, she is also supposed to be taking her ARVs every day.) She should also understand that OCs are not 100% effective as typically taken (about 5% to 8% failures per year) even without any effect of the ARVs.

In my view, additional sensible approaches in such a situation include 1) providing a 50 mcg estrogen OC, or 2) using condoms consistently along with the OCs.

*Fortunately, the other major class of ARVs in first-line regimens, the nucleoside reverse transcriptase inhibitors, do not appear to so affect liver metabolism. However, a number of the protease inhibitors, which are recommended in second-line regimens, do speed it up as well.

The "Pearls" offer answers to commonly asked questions about family planning. These "Pearls" are prepared by Dr. James D. Shelton, Senior Medical Scientist, Office of Population, United States Agency for International Development (USAID)

Disclaimer: The information provided on this web site is not official U.S. Government information and does not represent the views or positions of the U.S. Agency for International Development, the U.S. Government or The Johns Hopkins University.