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  1. 1
    801588
    Peer Reviewed

    A preliminary pharmacokinetic and pharmacodynamic evaluation of depot-medroxyprogesterone acetate and norethisterone oenanthate.

    Fotherby K; Saxena BN; Shrimanker K; Hingorani V; Takker D; Diczfalusy E; Landgren B-M

    Fertility and Sterility. 1980 Aug; 34(2):131-9.

    2 populations attending WHO centers, one in Sweden and one in India, participated in a comparative, pilot trial of 2 increasingly popular injectable progestin-only female contraceptives, Depo-Provera and Norigest. The purpose of the study was to assess the pharmacokinetic and pharmacodynamic properties of the 2 formulations (depot medroxyprogesterone acetate and norethisterone enanthate). Differences were found between Swedish women and Indian women in their reactions to the 2 drugs: 1) Norigest was detectable in blood samples a significantly shorter time after injection of the agent in Indian women than in Swedish women; this difference was not apparent with Depo-Provera. 2) Although there was no difference at the 2 centers in the time of ovulation return for subjects receiving Norigest, 0 of 4 Swedish women ovulated more than 156 days after Depo-Provera injection, whereas all 4 Indian women ovulated within 73 days of Depo-Provera injection; in the Swedish women, the levels of medroxyprogesterone were undetectable at time of return to ovulation, whereas Indian women had levels of .6 ng/ml when ovulation resumed. 3) In both cultures, Depo-Provera users had significantly more episodes of bleeding and spotting than Norigest users. This preliminary report emphasizes the variety of responses possible to injection of different contraceptive progestins among various populations and points to the need for further culturally comparative studies.
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  2. 2
    776175

    Long-acting systemic contraceptives.

    BENAGIANO G

    In: Diczfalusy, E., ed. Regulation of human fertility. (Proceedings of the WHO Symposium on Advances in Fertility Regulation, Moscow, USSR, November 16-19, 1976) Copenhagan, Denmark, Scriptor, 1977. p. 323-360

    Long-acting systemic contraceptives inhibit fertility either at a central or peripheral level. In some instances, a mixed reaction is likely to be working: during the 1st portion of the drug's life-span the contraceptive effect is exerted at a hypothalamic central level, whereas later on--when ovulation is restored--the action is on the cervix or uterus. The most important factor holding back utilization of long-acting agents is serious interference with regularity of the menstrual cycle, and delivery systems must be devised with zero-order release rates to improve cycle control and acceptability. Monthly injectables consisting of synthetic progestins alone proved unsuitable for contraception because of frequent and prolonged amenorrhea. Addition of an estrogenic substance helped cycle control, and a dihydroxyprogesterone acetophenide plus estradiol enanthate combination seems most worthy of clinical investigation; so far, 15,000 woman-months of experience have yielded no unwanted pregnancies. Few bleeding pattern irregularities were reported, but premenstrual tension, dysmenorrhea, and libido changes occurred. Reversibility of drug-induced anovulation has been shown by spontaneous ovulation resumption 12-42 weeks after cessation. Tri-monthly injections of Depo Provera resulted in pregnancy rates averaging .5/100 woman-years of use. Biannual injectable and sustained release systems are discussed and data are presented.
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