A pilot study of depot medroxyprogesterone acetate pharmacokinetics and weight gain in adolescent females.

OBJECTIVE: To explore the relationship between medroxyprogesterone acetate (MPA) pharmacokinetic (PK) parameter estimates and weight gain. STUDY DESIGN: Prospective study of adolescents (N=40; age 12-21 years) initiating DMPA. PK parameters were calculated: maximum MPA concentration (Cmax, ng/mL), time to Cmax (Tmax, days) and elimination rate constant (ng/mL/day). Optimal PK cut points were determined for predicting body mass index (BMI) increase ≥10%. RESULTS: Cmax <2.88 ng/mL and elimination rate constant <0.021 ng/mL/day were associated (p<.05) with BMI increase ≥10%. Elimination rate constant was most predictive of weight gain. CONCLUSIONS: PK evaluation may help identify adolescents at risk of excessive DMPA-associated weight gain.