Abstract
The goal of hormonal therapy in treating gender dysphoria is to maintain cross-sex hormone levels in the normal physiological range for the desired gender. Estrogen is the mainstay of hormonal therapy for male to female transgender patients. Efavirenz, a non-nucleoside reverse-transcriptase inhibitor, has been one of the most commonly prescribed antiretroviral therapies (ARTs). However, this regimen has also given rise to the most clinically significant drug-drug interactions between ARTs and hormone-based contraceptives. We discuss here three transgender HIV-positive women in whom efavirenz effected the metabolism of orally administered estradiol (and probably medroxyprogesterone).