Drug-drug interactions between antiretroviral drugs and feminizing hormones among trans women living with HIV in Toronto and Montreal (The Trans DDI) Study 

We’re running this study to see what effects (if any) common feminizing hormone regimens have on ART medications and vice versa. This is an important question for many reasons. Firstly, trans women around the world face a higher risk for HIV than cisgender folks due to biological and sociohistorical factors related to transphobia and intersecting forms of marginalization. Here’s a link to an article with more information!

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The same forces that put trans women at a higher risk for HIV also make it harder for trans women to access safe and consistent treatment and care—trans women living with HIV have also been found to have lower rates of access, usage, and adherence to antiretroviral therapy. An explanation for this is due to concerns about negative interactions between ART drugs and feminizing hormones, especially that ART medications may weaken the effect of feminizing hormones and even cause harm. Feminizing hormones are so vital to trans women’s lives that many will choose them over ART medications if they feel they must make a choice. And it’s not just trans women who have these concerns, but healthcare providers too—studies have shown that many healthcare providers withhold feminizing hormones from trans women living with HIV.  This can result in folks finding the medications outside of healthcare contexts, risking dangerous side effects and taking medications without medical supervision.

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Now onto some good news – our study is trying to address the concerns mentioned above. We have good reason to believe that there aren’t drug-drug interactions between common ART medications and oral estradiol (a feminizing hormone regimen that a lot of trans women in Canada take). Our study will be comparing estradiol levels between trans women living with HIV, trans women living without HIV, and cisgender (cis) women living with HIV. We expect that estradiol concentrations will be consistent across all three groups. 

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With this study, we want to make sense of the science behind drug-drug interactions and, depending on our findings, reassure both healthcare providers and trans women living with HIV that their medications are safe to take and all their healthcare needs can be met. This is a critical step towards our overall goal and ideal healthcare scenario. We’re working towards a model of shared decision-making where all parties have access to information about ART medications and feminizing hormones, allowing both critical treatment regimens to be prescribed safely and equitably.