Norethisterone, the active form of<unk> E. Pharmacodynamics<unk> E is a prodrug of norethisterone in the body. Upon reaching circulation, it is rapidly converted into norethisterone by esterases. Hence, as a prodrug of norethisterone,<unk> E has essentially the same effects as norethisterone, acting as a potent progestogen with additional weak androgenic and estrogenic activity (the latter via its metabolite ethinylestradiol).<unk> A has some progestogenic activity of its own, but it is unclear if<unk> E does similarly.<unk> E is of about 38% higher molecular weight than norethisterone due to the presence of its C17β<unk>  ester. Pharmacokinetics Norethisterone and ethinylestradiol levels over 8 weeks after a single intramuscular injection of 200 mg<unk> E in premenopausal women. A single intramuscular injection of 50 to 200 mg<unk> E in oil solution has been found to have a duration of action of 11 to 52 days in terms of clinical biological effect in the uterus and on body temperature in women. Similarly to oral norethisterone and norethisterone acetate, intramuscular<unk> E has been found to form ethinylestradiol as an active metabolite. With a single intramuscular injection of 200 mg<unk> E in premenopausal women, the mean maximum concentration of ethinylestradiol was 32% of that of a combined oral contraceptive containing 30 μg ethinylestradiol, the maximum equivalent oral dose of ethinylestradiol observed in the first few days of exposure was 20.3 μg/day, and the mean equivalent oral dose of ethinylestradiol over 8 weeks was 4.41 μg/day. As such, the exposure to ethinylestradiol was described as markedly lower than that of an oral contraceptive containing 30 μg ethinylestradiol. The estimated conversion rate of<unk> E into ethinylestradiol was 0.1%, which was much lower than that observed for oral norethisterone and<unk>  (0.2–1.0%), likely due to the lack of the first pass through the liver with parenteral administration. In accordance with the low levels of ethinylestradiol produced, no increase rates of thromboembolism or hepatic adenoma have been observed in post-authorization data of intramuscular<unk> E, and the medication does not resemble combined oral contraceptives containing ethinylestradiol in its safety profile.
Norethisterone enanthate
Norethisterone acetate
Nandrolone hydrogen succinate
Nandrolone phenylpropionate
Nandrolone furylpropionate
Androstanolone benzoate
Nandrolone decanoate
Nandrolone caproate