Effect of Coadministration of Etonogestrel Implant and Antiretroviral Therapies Containing Efavirenz or Lopinavir/Ritonavir on the Metabolism of Women Living with HIV/AIDS

Abstract

IntroductionUnplanned pregnancy is a health problem affecting all countries, particularly developing countries [1]. In vulnerable populations, the rate of unplanned pregnancies is even higher than that of general population. In Brazil, the rate of unplanned pregnancies among women living with HIV infection/AIDS exceeds 70% [2], whereas this rate is 55.4% among the general population [3]. Adequate contraception prevents unintended pregnancies, unsafe abortions, and maternal and newborn deaths, and helps to prevent vertical transmission of HIV infection [4].Family planning of women living with HIV infection/AIDS has a direct effect on their health and is a key strategy of the World Health Organization (WHO) to reduce vertical transmission [5]. In Brazil, the vertical transmission rate decreased to 33.3% in the last 10 years [6]. However, considering the high rates of unplanned pregnancy among these women, investment in family planning could contribute to further decrease vertical transmission rates. A 50% decrease in the number of births among women living with HIV infection/AIDS would be associated with a decrease from 27% to 5% in vertical transmission rate, resulting in an approximately 90% decrease in the number of children with HIV infection [7].In Brazil, since 2013, the number of people using antiretroviral therapy (ART) increased to 30%, and most of this population is of reproductive age [8]. Thus, the safety of hormonal contraceptive coadministration with the ARTs most often used by women living with HIV infection/AIDS must be known when prescribing hormonal contraceptives to these women. A recent study that evaluated the pharmacokinetic interaction between the two ART regimens most commonly used in Brazil showed that co-administration of etonogestrel (ENG) implant, the most effective contraceptive available, with ART containing lopinavir/ritonavir resulted in a 52% increase in ENG bioavailability, whereas co-administration with ART containing AbstractBackground: Concomitant use of antiretroviral therapy (ART) and hormonal contraceptives should be safe for women while maintaining medication efficacy without causing significant immunological or metabolic changes. However, the metabolic effect of the concomitant use of etonogestrel (ENG)-releasing implant and commonly used ARTs is not known.