Implications for medication dosing for transgender patients: A review of the literature and recommendations for pharmacists.

PURPOSE: Transgender patients face considerable healthcare disparities. Improved means of recognizing transgender patients and understanding their medical needs is important to provide optimal care. The electronic medical record (EMR) of our health system allows for differentiation of gender identity, legal sex, and sex at birth. With EMR recognition of transgender patients, a recommendation for estimating creatinine clearance (CLcr) and ideal body weight (IBW) was needed to standardize medication dosing. SUMMARY: The literature was reviewed for evidence on the effect of gender-affirming hormone therapy on serum creatinine concentration and lean body mass. Findings informed a recommendation for drug dosing based on CLcr and IBW in transgender patients. Four studies that reported the effect of hormone therapy on biometric laboratory values were found. Three studies reported that values of transgender patients more closely resembled the standard values of their gender identity vs sex at birth after hormone therapy; 1 study reported a range of values that more closely resembled those associated with sex at birth while still overlapping with values associated with gender identity. Consequently, it was recommended that pharmacists dose medications based on CLcr and IBW calculations consistent with gender identity after a patient has been on hormone therapy for 6 months or longer. CONCLUSION: Providing optimal care to transgender patients includes considering the effect of gender-affirming hormone therapy on overall physiology. Consistently using the appropriate CLcr and IBW calculations for each patient ensures safe and effective care. Additional studies are needed to confirm the effect of hormone therapy on renal clearance and lean body mass.