Concentration of depot medroxyprogesterone acetate and pain scores in adolescents: a randomized clinical trial

A prospective, single-blinded, randomized trial was initiated to determine whether injection site pain differed in adolescents receiving two concentrations of 150 mg of depot medroxyprogesterone acetate (DMPA). Ninety-five adolescents seeking injectable contraception were randomized to receive 150 mg of DMPA as follows: a deltoid injection of 1.0 mL from a single-unit-dose vial containing 150 mg/mL or 0.38 mL from a multidose vial containing 400 mg/mL of DMPA. A visual analogue scale was measured at each visit and cumulatively compared between the groups. Continuation rates were tabulated. The report of pain for the multidose vial group was significantly higher than for the unit-dose vial group (p<.003). The dropout rates for both groups were high at 1 year and were not statistically different (multidose group=64% and unit-dose group=77%). Twenty percent of the subjects in the multidose group vs. 22% in the unit-dose group discontinued due to bleeding irregularities. The concentrated form of DMPA led to greater pain at the injection site than did the less concentrated form, but this did not lead to higher discontinuation rates among adolescents.