Coadministration with Atazanavir/Ritonavir could increase etonogestrel exposure and therefore is not expected to impair the contraceptive efficacy of etonogestrel. Still, precaution should be taken when using combined hormonal vaginal contraceptives on Protease Inhibitors and alternative contraceptive methods should be considered.
Atazanavir/Ritonavir versus Etonogestrel
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Study Design
This was a non-blinded international study of ARV PK in pregnancy and postpartum. N=24 post-partum women who desired to use etonogestrel (ENG) implant while subsequently taking ARV regimens for at least 2 weeks. PK sampling was taken before 6 to 7 weeks after insertion.
Study Results
Etonogestrel is metabolized by CYP3A4. Coadministration of lopinavir/ritonavir and etonogestrel implants increased etonogestrel AUC, Cmax and Cmin by 52%, 61% and 34%, respectively, suggesting that lopinavir/ritonavir may not impair the efficacy of etonogestrel implants. Similarly, coadministration with atazanavir could potentially increase etonogestrel exposure and therefore is not expected to impair the contraceptive efficacy of etonogestrel when administered as an implant.
Study Conclusions
Per the authors, co-administration resulted in adequate ENG concentrations as well as no significant change in ATV/r exposure, implying that there should not be a change in efficacy of the implant or the ARV therapy.
References
Kreitchman, Stek, Best, Capparelli. Interaction between etonogestrel-releasing implant and 3 antiretroviral regimens [abstract]. Conference On Retroviruses And Opportunistic Infections. Seattle, WA, USA. 2017; February 2017.
Atazanavir/Ritonavir versus Etonogestrel
^
Study Design
This was a non-blinded international study of ARV PK in pregnancy and postpartum. N=24 post-partum women who desired to use etonogestrel (ENG) implant while subsequently taking ARV regimens for at least 2 weeks. PK sampling was taken before 6 to 7 weeks after insertion.
Study Results
Etonogestrel is metabolized by CYP3A4. Coadministration of lopinavir/ritonavir and etonogestrel implants increased etonogestrel AUC, Cmax and Cmin by 52%, 61% and 34%, respectively, suggesting that lopinavir/ritonavir may not impair the efficacy of etonogestrel implants. Similarly, coadministration with atazanavir could potentially increase etonogestrel exposure and therefore is not expected to impair the contraceptive efficacy of etonogestrel when administered as an implant.
Study Conclusions
Per the authors, co-administration resulted in adequate ENG concentrations as well as no significant change in ATV/r exposure, implying that there should not be a change in efficacy of the implant or the ARV therapy.
References
Scarsi, K, Cramer, S, Gingrich, D. Vaginal contraceptive hormone exposure profoundly altered by efv- and atv/r-based art. Conference On Retroviruses And Opportunistic Infections. Boston. 2018; March 2018.
Atazanavir/Ritonavir versus Etonogestrel
^
Study Design
A vaginal ring releasing Etonogestrel/Ethinyl Estradiol (ENG/EE) 120/15 mcg/day was inserted at entry in three groups of participants: (1) not yet receiving ART (control group; n=25); (2) ART containing efavirenz EFV 600mg daily (EFV group; n=25); (3) ART containing atazanavir/ritonavir ATV/r 300/100mg daily (ATV/r group; n=24). Participants returned on days 7, 14, and 21 for single measurements of ENG and EE PK, assessed by a validated LC/MS/MS method. Plasma hormone PK exposure was compared between each ART group and the control group at each visit by geometric mean ratio (GMR) with 90% CI, and by Wilcoxon-rank sum at the primary endpoint (day 21).
Study Results
Compared to the control group, participants in the EFV group had 76-79% lower ENG and 53-57% lower EE over 21 days (all p<0.001). In contrast, participants in the ATV/r group had 71-79% higher ENG (all p<0.001), yet 29-35% lower EE (p=0.066, 0.032 and 0.004 for days 7, 14 and 21, respectively) over 21 days compared to the control group. The GMR (90% CI) for ENG and EE concentrations for ATV: Control at Day 21 were 1.74 (1.38-2.20) and 0.65 (0.50-0.84) respectively.
Study Conclusions
Women on ATV/r-based ART should consider an alternative contraception method or barrier contraception in addition to the vaginal ring until the clinical relevance of these PK changes is better understood.
References
Scarsi, K, Cramer, S, Gingrich, D. Vaginal contraceptive hormone exposure profoundly altered by efv- and atv/r-based art. Conference On Retroviruses And Opportunistic Infections. Boston. 2018; March 2018.
Atazanavir/Ritonavir versus Etonogestrel
^
Study Design
A vaginal ring releasing Etonogestrel/Ethinyl Estradiol (ENG/EE) 120/15 mcg/day was inserted at entry in three groups of participants: (1) not yet receiving ART (control group; n=25); (2) ART containing efavirenz EFV 600mg daily (EFV group; n=25); (3) ART containing atazanavir/ritonavir ATV/r 300/100mg daily (ATV/r group; n=24). Participants returned on days 7, 14, and 21 for single measurements of ENG and EE PK, assessed by a validated LC/MS/MS method. Plasma hormone PK exposure was compared between each ART group and the control group at each visit by geometric mean ratio (GMR) with 90% CI, and by Wilcoxon-rank sum at the primary endpoint (day 21).
Study Results
Compared to the control group, participants in the EFV group had 76-79% lower ENG and 53-57% lower EE over 21 days (all p<0.001). In contrast, participants in the ATV/r group had 71-79% higher ENG (all p<0.001), yet 29-35% lower EE (p=0.066, 0.032 and 0.004 for days 7, 14 and 21, respectively) over 21 days compared to the control group. The GMR (90% CI) for ENG and EE concentrations for ATV: Control at Day 21 were 1.74 (1.38-2.20) and 0.65 (0.50-0.84) respectively.
Study Conclusions
Women on ATV/r-based ART should consider an alternative contraception method or barrier contraception in addition to the vaginal ring until the clinical relevance of these PK changes is better understood.
References
Scarsi, K, Cramer, S, Gingrich, D. Vaginal contraceptive hormone exposure profoundly altered by efv- and atv/r-based art. Conference On Retroviruses And Opportunistic Infections. Boston. 2018; March 2018.
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