Exploring Safety in Gender-Affirming Hormonal Treatments: An Observational Study on Adverse Drug Events Using the Food and Drug Administration Adverse Event Reporting System Database

Background: People with gender dysphoria are treated with hormone therapy for gender reassignment. The indication of this therapy was initially for the opposite sex, and information on potential adverse drug reaction (ADR) is lacking.Objective: To describe ADR associated with gender transition medication in transgender individuals reported to the US Food and Drug Administration Adverse Event Reporting System (FAERS) database.Methods: Data from the FAERS database up to June 2023 were examined, focusing on reports of gender transition medication use in the context of gender dysphoria. The ADRs were categorized using the Medical Dictionary for Regulatory Activities at both Preferred Term and System Organ Class (SOC) levels. Descriptive statistics summarized report counts, medication types, indications, and ADR severity.Results: For individuals assigned female at birth undergoing gender transition to male (transgender men), 82 reports (230 ADRs) were analyzed, with an average age of 29.5 years. Transgender hormonal therapy was cited in 72% of reports, predominantly from the United States (67.1%). A striking 88% were categorized as serious ADRs, primarily SOC injury, poisoning, and procedural complications (26.5%), followed by psychiatric disorders (14.8%) and nervous system disorders (12.2%). Among those assigned sex male at birth transitioning to female (transgender women) (81 reports, 237 ADRs), mean age was 33.3 years, with 58% indicating use for gender dysphoria. A significant proportion (53.6%) were serious ADRs, primarily SOC: injury, poisoning, and procedural complications (26.6%).Conclusions and Relevance: The FAERS data reveal significant ADRs in transgender individuals using hormone therapy, sometimes unintended for their recipient gender. Population-level studies are crucial to enhance transgender health care. Spontaneous surveillance databases like FAERS illuminate off-label ADRs, urging health care providers to approach hormone therapies with informed caution.