Pharmacokinetic study of different doses of Depo Provera

Doses of DepoProvera of 25, 50, 100 and 150mg were administered to four groups of women. The mean time for the return of follicular and luteal activity increased with increasing dose of DepoProvera. Luteal activity was suppressed for a longer period than follicular activity. None of the women receiving the two higher doses of DepoProvera showed a return of luteal function within 100 days of injection. The period for which medroxyprogesterone acetate (MPA) was detectable in serum increased with increasing dose but the values for the 100 and 150mg doses were not significantly different. There was a significant correlation between the concentration of MPA in blood and the return of follicular and luteal function. It is suggested that in the population studied, 100mg DepoProvera would be as effective as the usual 150mg dose and that injection of 50mg DepoProvera would provide a contraceptive effect for two months. The dose of MPA in the monthly injectable CycloProvera could be substantially reduced without loss of effectiveness.