Combined oral contraceptives and antiretroviral PK/PD in Malawian women: pharmacokinetics and pharmacodynamics of a combined oral contraceptive and a generic combined formulation antiretroviral in Malawi

U.S. Medical Eligibility Criteria for Contraceptive Use, 2024

The 2024 U.S. Medical Eligibility Criteria for Contraceptive Use (U.S. MEC) comprises recommendations for the use of specific contraceptive methods by persons who have certain characteristics or medical conditions. These recommendations for health care providers were updated by CDC after review of the scientific evidence and a meeting with national experts in Atlanta, Georgia, during January 25-27, 2023. The information in this report replaces the 2016 U.S. MEC (CDC. U.S. Medical Eligibility Criteria for Contraceptive Use, 2016. MMWR 2016:65[No. RR-3]:1-103). Notable updates include 1) the addition of recommendations for persons with chronic kidney disease; 2) revisions to the recommendations for persons with certain characteristics or medical conditions (i.e., breastfeeding, postpartum, postabortion, obesity, surgery, deep venous thrombosis or pulmonary embolism with or without anticoagulant therapy, thrombophilia, superficial venous thrombosis, valvular heart disease, peripartum cardiomyopathy, systemic lupus erythematosus, high risk for HIV infection, cirrhosis, liver tumor, sickle cell disease, solid organ transplantation, and drug interactions with antiretrovirals used for prevention or treatment of HIV infection); and 3) inclusion of new contraceptive methods, including new doses or formulations of combined oral contraceptives, contraceptive patches, vaginal rings, progestin-only pills, levonorgestrel intrauterine devices, and vaginal pH modulator. The recommendations in this report are intended to serve as a source of evidence-based clinical practice guidance for health care providers. The goals of these recommendations are to remove unnecessary medical barriers to accessing and using contraception and to support the provision of person-centered contraceptive counseling and services in a noncoercive manner. Health care providers should always consider the individual clinical circumstances of each person seeking contraceptive services. This report is not intended to be a substitute for professional medical advice for individual patients; when needed, patients should seek advice from their health care providers about contraceptive use.

Women for science and science for women: Gaps, challenges and opportunities towards optimizing pre-exposure prophylaxis for HIV-1 prevention

Preventing new HIV infections remains a global challenge. Young women continue to bear a disproportionate burden of infection. Oral pre-exposure prophylaxis (PrEP), offers a novel women-initiated prevention technology and PrEP trials completed to date underscore the importance of their inclusion early in trials evaluating new HIV PrEP technologies. Data from completed topical and systemic PrEP trials highlight the role of gender specific physiological and social factors that impact PrEP uptake, adherence and efficacy. Here we review the past and current developments of HIV-1 prevention options for women with special focus on PrEP considering the diverse factors that can impact PrEP efficacy. Furthermore, we highlight the importance of inclusion of female scientists, clinicians, and community advocates in scientific efforts to further improve HIV prevention strategies.

Interactions between Hormonal Contraception and Anti-Retroviral Therapy: An Updated Review

Purpose of review

Hormonal contraception provides women living with HIV the ability to control their fertility and avoid pregnancy-related morbidity. Due to shared metabolic pathways, there has been concern over drug-drug interactions between hormonal contraception and anti-retroviral therapy, which may affect the drugs' safety and efficacy. This article aims to provide an updated review of the most recent data around hormonal contraceptives and anti-retroviral therapy.

Recent findings

Prior data have suggested possible pharmacologic interactions between certain hormonal contraceptives and anti-retroviral therapy. The most significant interactions implicated include those between progestin-based contraceptive implants and efavirenz as well as between combined hormonal contraceptives and protease inhibitors. Most past studies, however, feature small sample sizes with few clinical outcomes reported.

Summary

Recent data since 2017 have largely affirmed prior studies on this topic, showing possible pharmacokinetic relationships between certain contraceptives and anti-retrovirals. Notably, while the effectiveness of progestin-based contraceptives, specifically the implant, appears reduced with efavirenz use, the overall effectiveness may remain higher than most other contraceptive methods. Larger studies are needed to provide further guidance before contraceptive-prescribing recommendations can be changed.

Effects of ritonavir-boosted protease inhibitors on combined oral contraceptive pharmacokinetics and pharmacodynamics in HIV-positive women

OBJECTIVE

To assess the pharmacokinetics of combined oral contraceptive (COC) components and prevalence of ovulation in HIV-positive women using ritonavir-containing antiretroviral regimens compared to those using regimens previously found not to interact with COCs or not using any antiretrovirals.

STUDY DESIGN

We conducted a prospective cohort pharmacokinetic pilot study comparing the pharmacokinetics of levonorgestrel (LNG) and ethinyl estradiol (EE) in HIV-positive women taking ritonavir-containing antiretroviral regimens to those in women using non-ritonavir-containing regimens or no antiretrovirals. Participants received COCs containing LNG/EE 150/30 mcg for 21 days. Beginning day 21, we collected serial blood samples over 72 h. The primary outcome was area under the curve (AUC) of LNG, with secondary outcomes including other LNG pharmacokinetic measures, EE pharmacokinetics and ovulation as measured by serum progesterone.

RESULTS

Pharmacokinetic parameters of LNG showed a trend toward increased exposure in women on ritonavir. LNG AUClast increased by 32.6% (312±60.9 vs. 243±82.6 ng/mL*h, p=.033, n=5) in women taking ritonavir compared to the control group (n=10). The Cmax (9.68±1.81 vs. 7.62±2.29 ng/mL) and Cmin (4.97±1.15 vs. 3.70±1.29 ng/mL) were also higher in the ritonavir arm. After excluding the inconsistent users (n=2), CL of LNG was reduced in the ritonavir arm (p=.032). EE pharmacokinetic profiles were not different between groups. The progesterone concentrations were similar in women of both groups, and none were consistent with ovulation during the treatment cycle.

CONCLUSION

Women on ritonavir showed an approximately 30% increase in LNG exposure but no difference in EE exposure.

IMPLICATIONS

The current data suggest that ritonavir does not have a clinically significant impact on oral contraceptive pharmacokinetics.

Consensus Statement on the Use of Oral Contraceptive Pills in Polycystic Ovarian Syndrome Women in India

OBJECTIVE

To provide consensus recommendations for health-care providers on the use of oral contraceptive pills (OCPs) in polycystic ovarian syndrome (PCOS) women in India.

PARTICIPANTS

Extensive deliberations, discussions, and brainstorming were done with different fraternities (specialists) being involved. These included endocrinologists, gynecologists, reproductive endocrinologists, dermatologists, public health experts, researchers, and a project manager with a team to develop the guideline.

EVIDENCE

Published literature was retrieved through searches of Medline and The Cochrane Database from January 2003 to December 2017 using appropriate-controlled vocabulary (e.g., oral contraceptive pills, polycystic ovarian syndrome, long term outcomes, infertility). Clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies' publications and data were also reviewed to suggest the recommendations.

PROCESS

The working group for guideline committee included members from the PCOS Society (India), Indian Society for Assisted Reproduction, The Mumbai Obstetric and Gynecological Society, The Endocrine Society of India, Indian Association of Dermatologists, Venereologists and Leprologists, Cosmetic Dermatology Society (India), Academicians from Medical Colleges, National Institute for Research in Reproductive Health, and a Research Associate. The core team included five reproductive endocrinologists, five gynecologists, five dermatologists, three endocrinologists, two public health experts and one research associate.

CONCLUSIONS

This consensus statement provides the guidance/recommendations for Indian practitioners regarding the use of OCP in women with PCOS. PCOS is one of the common endocrinopathies encountered in gynecological/endocrine practice. The spectrum of this disorder may range from prepubertal girls with premature pubarche, young girls with hirsutism, acne and anovulatory cycles, married women with infertility, and elderly women. Although obesity is a common feature for most PCOS patients, 'lean PCOS' also exists. For several years, OCPs have played an important role in the symptom management of PCOS women. This is due to the fact that OCPs decrease the luteinizing hormone, reduce androgen production, and increase sex hormone-binding globulin, which binds androgens. Several new formulations of OCPs have been developed to decrease the side effects. This includes use of less androgenic progestins and lower doses of ethinyl estradiol. These consensus recommendations help the health provider to choose the right type of OCPs, which will alleviate the symptoms with least side effects. It also gives insight into the indications, contraindications, and concerns regarding its short, intermediate and long-term use.

Current and future contraceptive options for women living with HIV

INTRODUCTION

Among women living with HIV, half of the pregnancies are unintended. Effective contraception can prevent unintended pregnancies and consequently reduce maternal mortality and perinatal transmission of HIV. While contraceptive options available for all women also apply to women living with HIV, specific considerations exist to the use of contraception by women living with HIV.

AREAS COVERED

First, general principles guiding the use of contraception among women living with HIV are discussed, such as choice, method mix, relative effectiveness, and drug-drug interactions. Second, a detailed discussion of each contraceptive method and issues surrounding the use of that method, such as drug-drug interactions, follows. Third, future contraceptive options in advanced development for use by women or men are briefly discussed.

EXPERT OPINION

Contraceptive methods available to all women should also be accessible to women living with HIV. When the relative effectiveness of a contraceptive method is reduced, for example due to drug-drug interactions with antiretrovirals, the method should still be made available to women living with HIV with the appropriate information sharing and counseling. Greater research on various aspects of contraceptive use by women living with HIV and more comprehensive testing of co-administration of hormonal contraceptives and common medications used by these women are warranted.

Effect of Efavirenz on Endogenous Progesterone Concentrations and Contraceptive Outcomes among Ugandan HIV Infected Women Coadministering Ethinylestradiol/Levonorgestrel

This study assessed the effect of efavirenz mid-dose plasma concentrations on mid-luteal endogenous progesterone concentrations and contraceptive outcomes among 49 HIV infected women coadministering ethinylestradiol/levonorgestrel, including 34 HIV positive women on Highly Active Antiretroviral Therapy (HAART) and 15 HAART naïve HIV infected women, purposively selected from Mulago Hospital, Uganda. A blood sample was collected once between days 20 and 22 of each woman's menstrual cycle for measuring endogenous progesterone and efavirenz concentrations by electrochemiluminescence technology and High Performance Liquid Chromatography (HPLC), respectively. Descriptive statistical analysis and correlation and logistic regression analysis were done using SPSS v.21 and R3.1. Efavirenz showed a weak positive linear relationship with endogenous progesterone at efavirenz concentrations below 12 μg/ml. Based on serum endogenous progesterone, the observed hormonal contraceptives failure rate (24.5%) was higher than expected (maximum 8%). A higher proportion of HIV positive women on efavirenz based HAART (26.5%) was at risk of contraceptive failure than their HIV infected HAART naïve counterparts (20%) though it was not statistically significant (p = 0.63). Efavirenz mid-dose plasma concentrations seem to have no significant effect on mid-luteal endogenous progesterone concentrations and contraceptive outcomes among HIV infected Ugandan women coadministering ethinylestradiol/levonorgestrel oral pills.

The Effect of Gene Variants on Levonorgestrel Pharmacokinetics When Combined With Antiretroviral Therapy Containing Efavirenz or Nevirapine

Reduced levonorgestrel concentrations from the levonorgestrel contraceptive implant was previously seen when given concomitantly with efavirenz. We sought to assess whether single nucleotide polymorphisms (SNPs) in genes involved in efavirenz and nevirapine metabolism were linked to these changes in levonorgestrel concentration. SNPs in CYP2B6, CYP2A6, NR1I2, and NR1I3 were analyzed. Associations of participant demographics and genotype with levonorgestrel pharmacokinetics were evaluated in HIV-positive women using the levonorgestrel implant plus efavirenz- or nevirapine-based antiretroviral therapy (ART), in comparison to ART-naïve women using multivariate linear regression. Efavirenz group: CYP2B6 516G>T was associated with lower levonorgestrel log₁₀ C_max and log₁₀ AUC. CYP2B6 15582C>T was associated with lower log₁₀ AUC. Nevirapine group: CYP2B6 516G>T was associated with higher log₁₀ C_max and lower log₁₀ C_min . Pharmacogenetic variations influenced subdermal levonorgestrel pharmacokinetics in HIV-positive women, indicating that the magnitude of the interaction with non-nucleoside reverse transcriptase inhibitors (NNRTIs) is influenced by host genetics.

Drug interactions between hormonal contraceptives and antiretrovirals

OBJECTIVE

To summarize published evidence on drug interactions between hormonal contraceptives and antiretrovirals.

DESIGN

Systematic review of the published literature.

METHODS

We searched PubMed, POPLINE, and EMBASE for peer-reviewed publications of studies (in any language) from inception to 21 September 2015. We included studies of women using hormonal contraceptives and antiretrovirals concurrently. Outcomes of interest were effectiveness of either therapy, toxicity, or pharmacokinetics. We used standard abstraction forms to summarize and assess strengths and weaknesses.

RESULTS

Fifty reports from 46 studies were included. Most antiretrovirals whether used for therapy or prevention, have limited interactions with hormonal contraceptive methods, with the exception of efavirenz. Although depot medroxyprogesterone acetate is not affected, limited data on implants and combined oral contraceptive pills suggest that efavirenz-containing combination antiretroviral therapy may compromise contraceptive effectiveness of these methods. However, implants remain very effective despite such drug interactions. Antiretroviral plasma concentrations and effectiveness are generally not affected by hormonal contraceptives.

CONCLUSION

Women taking antiretrovirals, for treatment or prevention, should not be denied access to the full range of hormonal contraceptive options, but should be counseled on the expected rates of unplanned pregnancy associated with all contraceptive methods, in order to make their own informed choices.

Drug-Drug Interactions, Effectiveness, and Safety of Hormonal Contraceptives in Women Living with HIV

Family planning options, including hormonal contraceptives, are essential for improving reproductive health among the more than 17 million women living with HIV worldwide. For these women, prevention of unintended pregnancy decreases maternal and child mortality, as well as reduces the risk of perinatal HIV transmission. Similarly, treatment of HIV with antiretroviral therapy (ART) is essential for reducing morbidity and mortality among HIV-positive individuals, as well as preventing HIV transmission between sexual partners or from mother to child. Importantly, despite the benefits of hormonal contraceptives, barriers to effective family planning methods exist for HIV-positive women. Specifically, drug-drug interactions can occur between some antiretroviral medications and some hormonal contraceptives, which may influence both contraceptive efficacy and tolerability. In addition, safety concerns have been raised about the impact of hormonal contraceptives on HIV disease progression, tolerability, and the risk of female-to-male HIV transmission. This review article summarizes the potential for drug-drug interactions, tolerability, and contraceptive effectiveness when hormonal contraceptives are combined with ART. In addition, the evidence surrounding the influence of hormonal contraceptives on HIV transmission and HIV disease progression in women living with HIV are summarized.

Contraception for HIV-Infected Adolescents

Access to high-quality reproductive health care is important for adolescents and young adults with HIV infection to prevent unintended pregnancies, sexually transmitted infections, and secondary transmission of HIV to partners and children. As perinatally HIV-infected children mature into adolescence and adulthood and new HIV infections among adolescents and young adults continue to occur in the United States, medical providers taking care of such individuals often face issues related to sexual and reproductive health. Challenges including drug interactions between several hormonal methods and antiretroviral agents make decisions regarding contraceptive options more complex for these adolescents. Dual protection, defined as the use of an effective contraceptive along with condoms, should be central to ongoing discussions with HIV-infected young women and couples wishing to avoid pregnancy. Last, reproductive health discussions need to be integrated with discussions on HIV care, because a reduction in plasma HIV viral load below the level of detection (an "undetectable viral load") is essential for the individual's health as well as for a reduction in HIV transmission to partners and children.

Unintended Pregnancies Observed With Combined Use of the Levonorgestrel Contraceptive Implant and Efavirenz-based Antiretroviral Therapy: A Three-Arm Pharmacokinetic Evaluation Over 48 Weeks

BACKGROUND

Levonorgestrel subdermal implants are preferred contraceptives with an expected failure rate of <1% over 5 years. We assessed the effect of efavirenz- or nevirapine-based antiretroviral therapy (ART) coadministration on levonorgestrel pharmacokinetics.

METHODS

This nonrandomized, parallel group, pharmacokinetic evaluation was conducted in three groups of human immunodeficiency virus-infected Ugandan women: ART-naive (n = 17), efavirenz-based ART (n = 20), and nevirapine-based ART (n = 20). Levonorgestrel implants were inserted at baseline in all women. Blood was collected at 1, 4, 12, 24, 36, and 48 weeks. The primary endpoint was week 24 levonorgestrel concentrations, compared between the ART-naive group and each ART group by geometric mean ratio (GMR) with 90% confidence interval (CI). Secondary endpoints included week 48 levonorgestrel concentrations and unintended pregnancies.

RESULTS

Week 24 geometric mean levonorgestrel concentrations were 528, 280, and 710 pg/mL in the ART-naive, efavirenz, and nevirapine groups, respectively (efavirenz: ART-naive GMR, 0.53; 90% CI, .50, .55 and nevirapine: ART-naive GMR, 1.35; 90% CI, 1.29, 1.43). Week 48 levonorgestrel concentrations were 580, 247, and 664 pg/mL in the ART-naive, efavirenz, and nevirapine groups, respectively (efavirenz: ART-naive GMR, 0.43; 90% CI, .42, .44 and nevirapine: ART-naive GMR, 1.14; 90% CI, 1.14, 1.16). Three pregnancies (3/20, 15%) occurred in the efavirenz group between weeks 36 and 48. No pregnancies occurred in the ART-naive or nevirapine groups.

CONCLUSIONS

Within 1 year of combined use, levonorgestrel exposure was markedly reduced in participants who received efavirenz-based ART, accompanied by contraceptive failures. In contrast, nevirapine-based ART did not adversely affect levonorgestrel exposure or efficacy.

CLINICAL TRIALS REGISTRATION

NCT01789879.

Pharmacogenetics of non-nucleoside reverse transcriptase inhibitors (NNRTIs) in resource-limited settings: Influence on antiretroviral therapy response and concomitant anti-tubercular, antimalarial and contraceptive treatments

The burden of human immunodeficiency virus (HIV) is mainly concentrated to resources-limited countries where the response to available antiretroviral therapy is often limited by the occurrence of toxicity or by the emergence of HIV drug resistance. Efavirenz and nevirapine are the antiretroviral drugs most prescribed in resources-limited countries as part of antiretroviral combination therapy. Their metabolism and conjugation are largely influenced by enzymatic genetic polymorphisms. The genetic variability of their metabolism could be associated to different metabolic phenotypes causing reduced patients' adherence because of toxicity or drug-drug interactions with concomitant therapies. The purpose of this review is to summarize published evidence on pharmacogenetic and pharmacokinetic aspects related to efavirenz and nevirapine, the influence of concomitant anti-tubercular, anti-malarial or contraceptive treatments, and the impact of human genetic variation and drug-drug interaction on the virologic and immunologic response to antiretroviral therapy in resources-limited countries.

Effectiveness of hormonal contraception in HIV-infected women using antiretroviral therapy

OBJECTIVE

The objective of this study is to assess whether antiretroviral therapy (ART) may diminish the effectiveness of hormonal contraceptive methods.

METHODS

Using data from 5153 HIV-infected women followed prospectively for 1-3 years in three HIV prevention studies in Africa, we compared incident pregnancy rates by contraceptive method (implant, injectable, oral or none) and ART use. Multivariable Cox regression models were used to determine adjusted hazard ratios (aHRs) and test interactions between each method and ART use.

RESULTS

During follow-up, 9% of women ever used implants, 40% used injectables and 14% used oral contraceptives; 31% of women ever used ART, mostly nevirapine (75% of ART users) or efavirenz-based (15%). Among women not using contraception, pregnancy rates were 13.2 and 22.5 per 100 women-years for those on and not on ART, respectively. Implants greatly reduced the incidence of pregnancy among both women on ART [aHR 0.06, 95% confidence interval (95% CI) 0.01-0.45] and not on ART (aHR 0.05, 95% CI 0.02-0.11). Injectables (aHR 0.18 on ART and aHR 0.20 not on ART) and oral contraceptives (aHR 0.37 on ART and aHR 0.36 not on ART) also reduced pregnancy risk, though by lesser degrees. ART use did not significantly diminish contraceptive effectiveness, although all methods showed nonstatistically significant reduced effectiveness when concurrently using efavirenz.

CONCLUSION

Hormonal contraceptive methods are highly effective in reducing pregnancy risk in HIV-infected women, including those concurrently using ART. Studies of potential interactions between ART and contraceptives should evaluate real-world effectiveness of contraceptive methods; in this study, implants were the most effective method to prevent pregnancy, even during ART use.

Pharmacokinetic and pharmacodynamic drug interactions between antiretrovirals and oral contraceptives

More than 50 % of women living with HIV in low- and middle-income countries are of reproductive age, but there are limitations to the administration of oral contraception for HIV-infected women receiving antiretroviral therapy due to drug-drug interactions caused by metabolism via the cytochrome P450 isoenzymes and glucuronidation. However, with the development of newer antiretrovirals that use alternative metabolic pathways, options for contraception in HIV-positive women are increasing. This paper aims to review the literature on the pharmacokinetics and pharmacodynamics of oral hormonal contraceptives when given with antiretroviral agents, including those currently used in developed countries, older ones that might still be used in salvage regimens, or those used in resource-limited settings, as well as newer drugs. Nucleos(t)ide reverse transcriptase inhibitors (NRTIs), the usual backbone to most combined antiretroviral treatments (cARTs) are characterised by a low potential for drug-drug interactions with oral contraceptives. On the other hand non-NRTIs (NNRTIs) and protease inhibitors (PIs) may interact with oral contraceptives. Of the NNRTIs, efavirenz and nevirapine have been demonstrated to cause drug-drug interactions; however, etravirine and rilpivirine appear safe to use without dose adjustment. PIs boosted with ritonavir are not recommended to be used with oral contraceptives, with the exception of boosted atazanavir which should be used with doses of at least 35 µg of estrogen. Maraviroc, an entry inhibitor, is safe for co-administration with oral contraceptives, as are the integrase inhibitors (INIs) raltegravir and dolutegravir. However, the INI elvitegravir, which is given in combination with cobicistat, requires a dose of estrogen of at least 30 µg. Despite the growing evidence in this field, data are still lacking in terms of large cohort studies, randomised trials and correlations to real clinical outcomes, such as pregnancy rates, in women on antiretrovirals and hormonal contraception.

Hormonal contraceptive use in HIV-infected women using antiretroviral therapy: A Systematic review

BACKGROUND

While extensive research has explored pharmacokinetic interactions between antiretroviral therapy and hormonal contraception, few studies have examined whether these interactions affect clinical outcomes. To address this gap, we conducted a systematic review of the literature that describes hormonal contraceptive among HIV infected women who also antiretroviral therapy, focusing on papers that address clinically important outcomes such as pregnancy or ovulation.

METHODS

An electronic literature search was conducted of PUBMED and OVID to identify all articles that addressed hormonal contraception co-administered with antiretroviral therapy published in English between 01 January 1990 and 30 October 2014. In addition, manual reference checks of all articles of interest were conducted to identify articles not captured in the electronic search. Our search criteria identified 405 records. The title and abstract of data reports retrieved via the search were reviewed to identify potential articles of interest. Those with any indication of the main outcomes of interest were considered for inclusion (N=162). Abstracts were then reviewed to identify those manuscripts that would merit a review of the full text version (N=64). Eight articles that addressed the outcomes of interest were identified. The Newcastle-Ottawa Scale was used to assess the quality of these articles.

RESULTS

The studies reviewed were limited in a number of ways that precluded their providing a rigorous assessment of the efficacy of contraception when co-administered with antiretroviral therapy.

DISCUSSION

None of the studies were of adequate quality to provide the guidance that providers and HIV infected women need when considering contraceptive options. High quality, well-powered studies are required to address the efficacy of hormonal contraception when co-administered with antiretroviral therapy.

Nevirapine-based antiretroviral therapy does not reduce oral contraceptive effectiveness

OBJECTIVE

To evaluate the effect of nevirapine-containing antiretroviral therapy (ART) on combined oral contraceptive (COC) effectiveness.

DESIGN

Nonrandomized prospective clinical trial.

METHODS

We enrolled HIV-infected women aged 18-35 years in South Africa and Uganda who had regular menses, were sexually active, and had no medical contraindications to COC use. We enrolled 196 women taking nevirapine-containing ART and 206 women not yet eligible for ART as a control group. We treated all participants with low-dose COCs. Our main outcomes were ovulation and pregnancy rates. We estimated ovulation in the first two cycles using weekly serum progesterone and tested for pregnancy monthly for 24 weeks.

RESULTS

The median age of participants was 29 and their median CD4 cell count was 486. In the ART group, 43 of 168 (26%) ovulated in cycle 1, 30 of 163 (18%) in cycle 2, and 18 of 163 (11%) in both cycles. In the non-ART group, 26 of 168 (16%) ovulated in cycle 1, 31 of 165 (19%) in cycle 2, and 20 of 165 (12%) in both cycles. We found no significant difference in ovulation rates between groups: unadjusted odds ratio 1.36 (95% confidence interval 0.85-2.18). Pregnancy rates also did not differ: 10.0 per 100-women-years in the ART group and 10.1 per 100-women-years in the non-ART group. Self-reported COC adherence, condom use, vaginal bleeding, and adverse events were similar. Five serious adverse events were reported, all in the non-ART group.

CONCLUSION

ART use did not affect risk of ovulation or pregnancy in women taking COCs, suggesting that nevirapine-containing ART does not interfere with COC contraceptive effectiveness.

Drug interactions between antiretrovirals and hormonal contraceptives

INTRODUCTION

Significant advances in antiretroviral therapy have transformed HIV into a chronic manageable disease, and millions of women living with HIV now have the opportunity to reconsider their reproductive choices, be it contraception or pregnancy planning. Hormonal contraceptives are metabolized by cytochrome P450 isoenzymes and sulfate and glucuronide conjugation in the liver. Many antiretrovirals have inducing or inhibiting effects on the cytochrome P450 system. As such, the pharmacokinetics of hormonal contraceptives can be affected by antiretroviral therapy with potential for significant clinical impact.

AREAS COVERED

This article presents the pharmacology and metabolism of selected antiretrovirals and hormonal contraceptives, and highlights the potential interactions between these two classes of drugs. Furthermore, the authors present the pharmacokinetic evidence of interactions from available clinical trials, product monographs, and international conference abstracts.

EXPERT OPINION

Drugs most likely to interact with combined oral contraceptives, transdermal and implant contraceptives include protease inhibitors, the NNRTIs efavirenz and nevirapine, and cobicistat-boosted elvitegravir. There do not appear to be significant pharmacokinetic interactions with depo-medroxyprogesterone or intrauterine systems and antiretrovirals, although further study is needed. Clinicians working with HIV-positive women need to know the significance of these interactions in order to properly counsel patients and prevent unplanned pregnancies.

Unraveling the divergent results of pre-exposure prophylaxis trials for HIV prevention

Although the balance of recent evidence supports the efficacy of antiretroviral (ARV)-based pre-exposure prophylaxis (PrEP) against HIV-1 infection, recent negative trial results are perplexing. Of seven trials with available HIV endpoints, three different products have been tested: tenofovir 1% vaginal gel, oral tenofovir disoproxil fumarate (TDF) tablets, and TDF/emtricitabine tablets. Six of these trials were conducted exclusively in sub-Saharan Africa; all found the products to be well tolerated, and four demonstrated effectiveness. Furthermore, the HIV Prevention Trial Network (HPTN) 052 trial recently confirmed that antiretroviral treatment leads to 96% reduction in transmission to HIV-negative partners in HIV-serodiscordant couples. These results, along with human and animal data, provide substantial evidence for the efficacy of antiretroviral-based HIV prevention. Yet assessment of oral TDF/emtricitabine in the FEM-PrEP study and of oral and vaginal tenofovir in the Microbicide Trial Network (MTN)-003 trial (VOICE) was stopped for futility. How do we make sense of these discrepant results? We believe that adherence is a key factor, although it cannot be the only factor. Expanding upon a recent editorial in the Lancet, we discuss the impact of suboptimal product adherence on PrEP efficacy in the context of variable drug concentration at the exposure site, integrity of the vaginal epithelium, and the role of acute infection.