Implanon® failure in an HIV-positive woman on antiretroviral therapy resulting in two ectopic pregnancies

Effect of patient genetics on etonogestrel pharmacokinetics when combined with efavirenz or nevirapine ART

BACKGROUND

We previously demonstrated that etonogestrel concentrations were 82% lower in women using etonogestrel contraceptive implants plus efavirenz-based ART compared with women not receiving ART.

OBJECTIVES

To investigate the genetic contribution to this previously observed drug-drug interaction through studying SNPs in genes known to be involved in efavirenz, nevirapine or etonogestrel metabolism in the same group of women.

PATIENTS AND METHODS

Here, we present a secondary analysis evaluating SNPs involved in efavirenz, nevirapine and etonogestrel metabolism and associated etonogestrel pharmacokinetics among 57 women, 19 not receiving ART (control group), 19 receiving efavirenz- (600 mg daily) based ART and 19 receiving nevirapine- (200 mg twice daily) based ART. Associations between patient genotype and etonogestrel pharmacokinetic parameters were determined through univariate and multivariate linear regression. This study was registered at clinicaltrials.gov (NCT02082652).

RESULTS

Within the control group, CYP2B6 983 T>C was associated with 27% higher etonogestrel Cmax and 28% higher AUC0-24weeks. In the efavirenz group CYP2B6 516 G>T was associated with 43% lower etonogestrel Cmin and 34% lower AUC0-24weeks. For participants receiving nevirapine, NR1I2 63396 C>T was associated with 39% lower etonogestrel Cmin and 37% lower AUC0-24weeks.

CONCLUSIONS

This study demonstrates the influence of pharmacogenetics on the extent of drug-drug interactions between etonogestrel and efavirenz- or nevirapine-based ART. Efavirenz plus the etonogestrel contraceptive implant results in a detrimental drug-drug interaction irrespective of patient genetics, which is worsened in women possessing variant alleles for these CYP2B6 SNPs.

Contraceptive implant failures among women using antiretroviral therapy in western Kenya: a retrospective cohort study

Background: Women living with HIV have the right to choose whether, when and how many children to have. Access to antiretroviral therapy (ART) and contraceptives, including implants, continues to increase in Kenya. Studies have reported drug-drug interactions leading to contraceptive failures among implant users on ART. This retrospective record review aimed to determine unintentional pregnancy rates among women 15-49 years of age, living with HIV and concurrently using implants and ART in western Kenya between 2011 and 2015.

Methods: We reviewed charts of women with more than three months of concurrent implant and ART use. Implant failure was defined as implant removal due to pregnancy or birth after implant placement, but prior to scheduled removal date. The incidence of contraceptive failure was calculated by woman-years at risk, assuming a constant rate.

Results: Data from 1,152 charts were abstracted, resulting in 1,190 implant and ART combinations. We identified 115 pregnancies, yielding a pregnancy incidence rate of 6.32 (5.27–7.59), with 9.26 among ETG and 4.74 among LNG implant users, respectively. Pregnancy incidence rates did not differ between EFV- and NVP-based regimens (IRR=1.00, CI: 0.71-1.43). No pregnancies were recorded among women on PI-based regimens, whereas pregnancy rates for efavirenz and nevirapine-containing regimens were similar, at 6.41 (4.70–8.73) and 6.44 (5.13–8.07), respectively. Pregnancy rates also differed significantly by implant type, with LNG implant users half as likely to experience pregnancy as ETG implant users (0.51, CI: 0.33-0.79, p>0.01).

Conclusions: Our findings highlight the implications of drug-drug interaction on women’s choices for contraception.

Pregnancies associated with etonogestrel implants in the UK: comparison of two 5-year reporting periods

OBJECTIVES

(1) To identify pregnancies associated with the use of the contraceptive implants Implanon and Nexplanon in the UK during two 5-year reporting periods. (2) To classify the possible reasons for device failure in cases reported for each implant. (3) To examine any differences between reasons for pregnancies associated with these products.

STUDY DESIGN

Extraction of data from the UK spontaneous reporting system for adverse drug reactions in relation to etonogestrel implants. Reports indicating pregnancy were identified for the periods 2005-2009 (Implanon) and 2012-2016 (Nexplanon). Possible reasons for failure of the method in each reported case were assigned to one of eight predetermined categories.

RESULTS

After exclusions, 229 Implanon and 234 Nexplanon cases contained sufficient information for analysis. True method failures accounted for a majority of the pregnancies in those using contraceptive implants (58%); the next most common cause was missing implants (26% of pregnancies). In all categories of cases, there was no difference in frequency of pregnancy when the two time periods were compared.

CONCLUSIONS

There is still potential for greater avoidance of pregnancies associated with etonogestrel implant use.

IMPLICATIONS

This study underscores the continuing need for taking a full drug history, timing the insertion on days 1-5 or according to recommended quick starting routines and palpating the arm after implant insertion.

Contraceptive implant failures among women using antiretroviral therapy in western Kenya: a retrospective cohort study

Background: Women living with HIV have the right to choose whether, when and how many children to have. Access to antiretroviral therapy (ART) and contraceptives, including implants, continues to increase due to a multitude of efforts. In Kenya, 4.8% of adults are living with HIV, and in 2017, 54% were receiving an efavirenz-based ART regimen. Meanwhile, 16.1% of all Kenyan married (and 10.4% of unmarried) women used implants. Studies have reported drug interactions leading to contraceptive failures among implant users on ART. This retrospective record review aimed to determine unintentional pregnancy rates among women 15-49 years of age, living with HIV and concurrently using implants and ART in western Kenya between 2011 and 2015. Methods: We reviewed charts of women with more than three months of concurrent implant and ART use. Implant failure was defined as implant removal due to pregnancy or birth after implant placement, but prior to scheduled removal date. The incidence of unintended pregnancy was calculated by woman-years at risk, assuming a constant rate. Results: Data from 1,152 charts were abstracted, resulting in 1,190 implant and ART combinations. We identified 115 pregnancies, yielding a pregnancy incidence rate of 6.32 (5.27–7.59), with 9.26 among ETG and 4.74 among LNG implant users, respectively. No pregnancies were recorded among women on non-NNRTI-based regimens, whereas pregnancy rates for efavirenz and nevirapine-containing regimens were similar, at 6.41 (4.70–8.73) and 6.44 (5.13–8.07), respectively. Conclusions: Our findings highlight the implications of drug interaction on women’s choices for contraception.

Concomitant contraceptive implant and efavirenz use in women living with HIV: perspectives on current evidence and policy implications for family planning and HIV treatment guidelines

Introduction: Preventing unintended pregnancies is important among all women, including those living with HIV. Increasing numbers of women, including HIV-positive women, choose progestin-containing subdermal implants, which are one of the most effective forms of contraception. However, drug–drug interactions between contraceptive hormones and efavirenz-based antiretroviral therapy (ART) may reduce implant effectiveness. We present four inter-related perspectives on this issue.

Discussion: First, as a case study, we discuss how limited data prompted country-level guidance against the use of implants among women concomitantly using efavirenz in South Africa and its subsequent negative effects on the use of implants in general. Second, we discuss the existing clinical data on this topic, including the observational study from Kenya showing women using implants plus efavirenz-based ART had three-fold higher rates of pregnancy than women using implants plus nevirapine-based ART. However, the higher rates of pregnancy in the implant plus efavirenz group were still lower than the pregnancy rates among women using common alternative contraceptive methods, such as injectables. Third, we discuss the four pharmacokinetic studies that show 50–70% reductions in plasma progestin concentrations in women concurrently using efavirenz-based ART as compared to women not on any ART. These pharmacokinetic studies provide the biologic basis for the clinical findings. Fourth, we discuss how data on this topic have marked implications for both family planning and HIV programmes and policies globally.

Conclusion: This controversy underlines the importance of integrating family planning services into routine HIV care, counselling women appropriately on increased risk of pregnancy with concomitant implant and efavirenz use, and expanding contraceptive method mix for all women. As global access to ART expands, greater research is needed to explore implant effectiveness when used concomitantly with newer ART regimens. Data on how HIV-positive women and their partners choose contraceptives, as well as information from providers on how they present and counsel patients on contraceptive options are needed to help guide policy and service delivery. Lastly, greater collaboration between HIV and reproductive health experts at all levels are needed to develop successful strategies to ensure the best HIV and reproductive health outcomes for women living with HIV.

Efavirenz decreases etonogestrel exposure: a pharmacokinetic evaluation of implantable contraception with antiretroviral therapy

OBJECTIVES

The primary objective of this study was to characterize the pharmacokinetics of etonogestrel (ENG) released from a contraceptive implant in Ugandan women living with HIV who were receiving efavirenz (EFV) or nevirapine (NVP)-based antiretroviral therapy (ART), compared with ART-naive women over 24 weeks.

DESIGN

Nonrandomized, parallel-group study with three arms: ART-naive, NVP, or EFV-based ART (N = 20/group).

METHODS

Sparse pharmacokinetic sampling of ENG, NVP, or EFV were performed at screening, entry, and then 1, 4, 12, and 24-week postimplant insertion. The primary endpoint was ENG concentrations at week 24, compared between the ART-naive group and each ART group, using geometric mean ratio (GMR) with 90% confidence intervals.

RESULTS

Sixty participants competed the 24-week study and data from 58 participants are included; one participant each was excluded from the NVP group and EFV group because of a sample processing error and ART nonadherence, respectively. At week 24, geometric mean ENG was 362, 341, and 66 pg/ml in the ART-naive, NVP, and EFV groups, respectively [GMR: NVP : ART-naive 0.94 (0.90-1.01); EFV : ART-naive 0.18 (0.17-0.20)]. NVP and EFV concentrations were lower at week 24 compared to preimplant [NVP: geometric mean 5.7 versus 6.8 mg/l, respectively, GMR 0.84 (0.83-0.85); EFV: geometric mean 3.6 versus 4.9 mg/l, respectively, GMR 0.73 (0.69-0.80)].

CONCLUSION

After 24 weeks of combined use, ENG exposure was 82% lower in women using EFV-based ART compared with ART-naive women. In contrast, NVP did not significantly impact ENG exposure. These results raise concerns about reduced effectiveness of implantable contraception for women taking EFV-based ART.

Contraceptive use among HIV-infected women and men receiving antiretroviral therapy in Lusaka, Zambia: a cross-sectional survey

Background

Family planning (FP) is an essential health service and an important part of comprehensive HIV care. However, there is limited information about the contraceptive needs of people living with HIV in sub-Saharan Africa, which in turn has hampered efforts to expand and integrate FP services into existing HIV programs.

Methods

We performed a cross-sectional survey to determine FP prevalence and predictors among HIV-positive women and men attending 18 public antiretroviral therapy (ART) clinics in Lusaka, Zambia. Trained peer counselors administered the 10-question survey to those seeking care for five days at each of the target sites.

Results

From February to April 2014, we surveyed 7,046 HIV-infected patients receiving routine HIV services. Use of modern contraception was reported by 69 % of female ART patients and 79 % of male ART patients. However, highly effective contraceptive use and dual method use were low among women (38 and 25 %, respectively) and men (19 and 14 %, respectively). HIV disclosure status (adjusted odds ratio (AOR) = 4.91, 95 % confidence interval (CI) = 3.32–7.24 for women, AOR = 3.58, 95 % CI = 2.39–5.38 for men) and sexual activity in the last 6 months (AOR = 5.80, 95 % CI = 4.51–7.47 for women, AOR = 6.24, 95 % CI = 3.51–11.08 for men) were associated with modern contraceptive use in multivariable regression. Most respondents said they would access FP services if made available within ART clinic.

Conclusions

While FP-ART integration may be a promising strategy for increasing FP service uptake, such services must focus on assessing sexual activity and advocating for dual method use to increase effective contraceptive use and prevent unintended pregnancies.

Canadian Contraception Consensus (Part 3 of 4): Chapter 8 - Progestin-Only Contraception

OBJECTIVE

To provide guidelines for health care providers on the use of contraceptive methods to prevent pregnancy and on the promotion of healthy sexuality.

OUTCOMES

Overall efficacy of cited contraceptive methods, assessing reduction in pregnancy rate, safety, ease of use, and side effects; the effect of cited contraceptive methods on sexual health and general well-being; and the relative cost and availability of cited contraceptive methods in Canada.

EVIDENCE

Published literature was retrieved through searches of Medline and The Cochrane Database from January 1994 to January 2015 using appropriate controlled vocabulary (e.g., contraception, sexuality, sexual health) and key words (e.g., contraception, family planning, hormonal contraception, emergency contraception). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies published in English from January 1994 to January 2015. Searches were updated on a regular basis in incorporated in the guideline to June 2015. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The quality of the evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). CHAPTER 8: PROGESTIN-ONLY CONTRACEPTION: Summary Statements Recommendations.

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.

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.

Pregnancy rates in HIV-positive women using contraceptives and efavirenz-based or nevirapine-based antiretroviral therapy in Kenya: a retrospective cohort study

BACKGROUND

Concerns have been raised about efavirenz reducing the effectiveness of contraceptive implants. We aimed to establish whether pregnancy rates differ between HIV-positive women who use various contraceptive methods and either efavirenz-based or nevirapine-based antiretroviral therapy (ART) regimens.

METHODS

We did this retrospective cohort study of HIV-positive women aged 15-45 years enrolled in 19 HIV care facilities supported by Family AIDS Care and Education Services in western Kenya between Jan 1, 2011, and Dec 31, 2013. Our primary outcome was incident pregnancy diagnosed clinically. The primary exposure was a combination of contraceptive method and efavirenz-based or nevirapine-based ART regimen. We used Poisson models, adjusting for repeated measures, and demographic, behavioural, and clinical factors, to compare pregnancy rates among women receiving different contraceptive and ART combinations.

FINDINGS

24,560 women contributed 37,635 years of follow-up with 3337 incident pregnancies. In women using implants, adjusted pregnancy incidence was 1.1 per 100 person-years (95% CI 0.72-1.5) for nevirapine-based ART users and 3.3 per 100 person-years (1.8-4.8) for efavirenz-based ART users (adjusted incidence rate ratio [IRR] 3.0, 95% CI 1.3-4.6). In women using depot medroxyprogesterone acetate, adjusted pregnancy incidence was 4.5 per 100 person-years (95% CI 3.7-5.2) for nevirapine-based ART users and 5.4 per 100 person-years (4.0-6.8) for efavirenz-based ART users (adjusted IRR 1.2, 95% CI 0.91-1.5). Women using other contraceptive methods, except for intrauterine devices and permanent methods, had 3.1-4.1 higher rates of pregnancy than did those using implants, with 1.6-2.8 higher rates in women using efavirenz-based ART.

INTERPRETATION

Although HIV-positive women using implants and efavirenz-based ART had a three-times higher risk of contraceptive failure than did those using nevirapine-based ART, these women still had lower contraceptive failure rates than did those receiving all other contraceptive methods except for intrauterine devices and permanent methods. Guidelines for contraceptive and ART combinations should balance the failure rates for each contraceptive method and ART regimen combination against the high effectiveness of implants.

FUNDING

None.

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.

Effect of antiretroviral therapy including lopinavir/ritonavir or efavirenz on etonogestrel-releasing implant pharmacokinetics in HIV-positive women

OBJECTIVE

Data on the interaction between the etonogestrel (ENG) implant and antiretroviral therapy are lacking. We evaluated the effect of 2 highly active antiretroviral therapy (HAART) regimens (1 including efavirenz and the other ritonavir-boosted lopinavir) on the pharmacokinetic (PK) parameters of an ENG-releasing implant in HIV-positive women.

DESIGN

Prospective nonrandomized PK study.

METHODS

Forty-five HIV-positive women who desired to use ENG implants were included: 15 had received zidovudine/lamivudine + lopinavir/ritonavir for ≥3 months (LPV/r-based HAART group), 15 had received zidovudine/lamivudine + efavirenz for ≥3 months (EFV-based HAART group), and 15 had not received HAART (non-HAART group). PK parameters were measured using ultra-performance liquid chromatography-mass spectrometry at baseline and 2, 4, 6, 8, 10, 12, 16, 20, and 24 weeks after implant placement.

RESULTS

The EFV-based HAART regimen was associated with a reduction in the bioavailability of ENG, which showed decreases of 63.4%, 53.7%, and 70% in the area under the curve (AUC), maximum concentration (Cmax), and minimum concentration (Cmin) of ENG, respectively, compared with the non-HAART group. The LPV/r-based HAART regimen was associated with an increase in ENG bioavailability, which showed 52%, 60.6%, and 33.8% increases in the ENG AUC, Cmax, and Cmin, respectively, compared with the non-HAART group.

CONCLUSIONS

The coadministration of EFV decreased the bioavailability of ENG released from the implant, which could impair contraceptive efficacy. However, the coadministration of LPV/r increased the bioavailability of ENG released from the implant, which suggests that this antiretroviral combination does not impair the ENG implant efficacy.

Effects of hormonal contraception on antiretroviral drug metabolism, pharmacokinetics and pharmacodynamics

Among women, human immunodeficiency virus type 1 (HIV-1) infection is most prevalent in those of reproductive age. These women are also at risk of unintended or mistimed pregnancies. Hormonal contraceptives (HCs) are one of the most commonly used methods of family planning worldwide. Therefore, concurrent use of HC among women on antiretroviral medications (ARVs) is increasingly common. ARVs are being investigated and have been approved for pre-exposure prophylaxis (PrEP), and therefore, drug-drug interactions must also be considered in HIV-1-negative women who want to prevent both unintended pregnancy and HIV-1 infection. This article will review four main interactions: (i) the effect of HCs on ARV pharmacokinetics (PK) and pharmacodynamics (PD) during therapy, (ii) the effect of ARVs on HC PK and PD, (iii) the role of drug transporters on drug-drug interactions, and (iv) ongoing research into the effect of HCs on pre-exposure prophylaxis PK and PD.

Effect of concurrent use of anti-retroviral therapy and levonorgestrel sub-dermal implant for contraception on CD4 counts: a prospective cohort study in Kenya

INTRODUCTION

Simultaneous use of contraceptive hormones and anti-retroviral therapy (ART) may theoretically lessen the effectiveness of both. Women on ART need assurance that hormonal contraception is safe and effective. The sub-dermal implant is an ideal product to study: low and steady progestin release and no adherence uncertainties. We sought to determine if the medications' effectiveness is compromised.

METHODS

We conducted a prospective cohort study among women on first line ART (stavudine or zidovudine and lamivudine+nevirapine). We recruited new implant users and matched them to women not using hormonal contraception, based on age and baseline CD4. Participants were followed prospectively for up to two years, recording serial CD4 measures and medical histories. We used generalized growth curve models and Wald chi-square tests to compare changes in CD4 counts across study groups. Prospective CD4 measures were censored (excluded) if any of the following events occurred: change in ART, implant removal or use of any hormonal contraception among controls. We examined incidence of opportunistic infection and pregnancy.

RESULTS

We matched 48 implant users to 33 non-hormonal controls. Over time, CD4 counts for both groups rose slightly but did not deviate significantly from each other (p=0.44). Opportunistic infection rates did not differ between the groups. None of the implant users and one of the non-hormonal controls became pregnant during follow-up.

CONCLUSIONS

This small study found concurrent use of contraceptive implants and ART to be safe and effective. Although other hormonal contraceptive products and ART regimens may interact in unknown ways, the results of this study are reassuring.

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.

Contraception for the HIV-positive woman: a review of interactions between hormonal contraception and antiretroviral therapy

BACKGROUND

Preventing unintended pregnancy in HIV-positive women can significantly reduce maternal-to-child HIV transmission as well as improve the woman's overall health. Hormonal contraceptives are safe and effective means to avoid unintended pregnancy, but there is concern that coadministration of antiretroviral drugs may alter contraceptive efficacy.

MATERIALS AND METHODS

We performed a literature search of PubMed and Ovid databases of articles published between January 1980 and February 2012 to identify English-language reports of drug-drug interactions between hormonal contraceptives (HCs) and antiretroviral drugs (ARVs). We also reviewed the FDA prescribing information of contraceptive hormone preparations and antiretrovirals for additional data and recommendations.

RESULTS

Twenty peer-reviewed publications and 42 pharmaceutical package labels were reviewed. Several studies of combined oral contraceptive pills (COCs) identified decreased serum estrogen and progestin levels when coadministered with certain ARVs. The contraceptive efficacy of injectable depot medroxyprogesterone acetate (DMPA) and the levonorgestrel intrauterine system (LNG-IUS) were largely unaffected by ARVs, while data on the contraceptive patch, ring, and implant were lacking.

CONCLUSIONS

HIV-positive women should be offered a full range of hormonal contraceptive options, with conscientious counseling about possible reduced efficacy of COCs and the contraceptive implant when taken with ARVs. DMPA and the LNG-IUS maintain their contraceptive efficacy when taken with ARVs.