ABSTRACT
BACKGROUND: A new progestin-only, nondaily depot medroxyprogesterone acetate (DMPA) SC injectable contraceptive suspension (104 mg/0.65 mL) has been developed. Clinical trials (including dose-ranging, pharmacokinetic/pharmacodynamic, and contraceptive efficacy studies) indicating the effectiveness of this new formulation were conducted primarily in white women. However, results of an early study by the World Health Organization suggested that in Thai women, medroxyprogesterone acetate (MPA) may be metabolized in <91 +/- 7 days (the range for effective suppression of ovulation established in clinical trials), resulting in a faster return to ovulation in this population. OBJECTIVES: This study was designed to determine the duration of ovulation suppression and investigate the pharmacokinetic profile of MPA after a single SC injection of DMPA 104 mg/0.65 mL in Asian women. It also assessed the effect of ethnicity and injection site on the duration of ovulation suppression. METHODS: : This was a single-center, single-dose, open-label outpatient trial conducted in Singapore in Asian women aged 18 to 40 years. After 1 control cycle, women with confirmed ovulation were randomized in a 1:1 ratio to receive an SC injection of DMPA 104 mg/0.65 mL in either the anterior thigh or the abdomen. Serum concentrations of MPA, progesterone, estradiol, luteinizing hormone, and follicle-stimulating hormone were measured during the 91-day dosing interval and for an additional 15 days thereafter. RESULTS: Twenty-four Asian women (mean [SD] age, 33.8 [43] years; range, 22.7-40.1 years; mean [SD] body mass index, 22.4 [3.0] kg/m(2)) belonging to 5 ethnic groups (Chinese, Filipino, Indian, Malaysian, and Thai) were included in the study Ovulation suppression was maintained throughout the 91-day dosing interval, regardless of ethnicity or injection site. Ovulation was suppressed for at least 112 days after injection in 23 (95.8%) women, as evidenced by maintenance of serum progesterone concentrations <4.7 ng/mL. The pharmacokinetic parameters for MPA in these Asian women were similar to those previously reported in white women. The most frequently reported adverse events were flulike symptoms and headache, all of mild to moderate intensity. No serious adverse events were reported. CONCLUSIONS: In this study, SC DMPA 104 mg/0.65 mL provided effective suppression of ovulation for at least 91 days in Asian women. Ethnicity and injection site had no effect on MPA profiles.
