A preliminary pharmacokinetic and pharmacodynamic evaluation of depot-medroxyprogesterone acetate and norethisterone oenanthate
Fotherby, K.; Saxena, B.N.; Shrimanker, K.; Hingorani, V.; Takker, D.; Diczfalusy, E.; Landgren, B.M.
Fertility and Sterility 34(2): 131-139
1980
ISSN/ISBN: 0015-0282 PMID: 7409232 DOI: 10.1016/s0015-0282(16)44895-8Document Number: 451326
A comparative pilot study was carried out in 2 WHO Collaborating Centers on Research and Training in Human Reproduction (New Delhi [India] and Stockholm [Sweden]) to assess the pharmacokinetic and pharmacodynamic properties of 2 injectable steroidal contraceptives, depot-medroxyprogesterone acetate (DMPA) and norethisterone enanthate (NET-OEN). The assessment also included a variety of biochemical and hematologic indices. The period during which NET was detectable in the blood following injection of NET-OEN was significantly shorter in Indian women than in Swedish women. No difference was apparent with DMPA. None of the 4 Swedish women ovulated until more than 156 days after injection of DMPA and until plasma medroxyprogesterone acetate (MPA) levels were undetectable. The 4 Indian women ovulated within 73 days of injection of DMPA, and MPA levels at this time were above 0.6 ng/ml. There was no difference between the 2 centers in the time of return of ovulation for subjects receiving NET-OEN. For women receiving DMPA, the number of days on which bleeding and spotting occurred and the number of episodes of bleeding were significantly higher than those of women receiving NET-OEN. There were no significant changes in any of the biochemical or hematologic analyses as a result of gestagen injection. This preliminary study suggests that responses to the 2 injectable contraceptives may vary in different populations and emphasizes the need for more detailed comparative investigations in those countries where the formulations are expected to be in widespread use.