Pharmacodynamics<unk>  is a potent, long-acting, and pure progestogen, possessing no androgenic, anabolic, antiandrogenic, estrogenic, antiestrogenic, glucocorticoid, mineralocorticoid, or teratogenic effects. It is approximately 20 to 25 times more potent than progesterone or hydroxyprogesterone<unk>  in animal bioassays when all are given by subcutaneous injection. In humans, 100 or 200 mg intramuscular<unk>  has been said to be equivalent to 1,000 mg intramuscular hydroxyprogesterone<unk> . Hence,<unk>  is approximately 5- to 10-fold more potent than hydroxyprogesterone<unk>  in humans. The biological effects of<unk>  in women have been studied. Like other potent progestins,<unk>  possesses potent antigonadotropic activity and is capable of markedly suppressing the gonadal production and circulating levels of sex hormones such as testosterone and estradiol. A clinical study found that 400 mg/week intramuscular<unk>  suppressed testosterone levels by 75% in men, while orchiectomy as a comparator reduced testosterone levels by 91%. Levels of luteinizing hormone, conversely, remained unchanged. In general, progestogens can maximally suppress testosterone levels by about 70 to 80%. In accordance with its lack of glucocorticoid activity,<unk>  has no anticorticotropic effects, and does not influence the secretion of adrenocorticotropic hormone. 17α-Hydroxyprogesterone has weak progestogenic activity, but C17α esterification results in higher progestogenic activity. Of a variety of different esters, the<unk>  (hexanoate) ester was found to have the strongest progestogenic activity, and this formed the basis for the development of<unk> , as well as other<unk>  progestogen esters such as hydroxyprogesterone<unk> .<unk>  has been found to decrease the weights of the prostate gland and seminal vesicles by 40 to 70% in adult male rats. It has been shown in canines to mediate these effects both via its antigonadotropic effects and by direct actions in these tissues.<unk>  decreases the uptake of testosterone into the prostate gland. It has also been found to have direct antiproliferative effects on human ovarian cancer cells in vitro.<unk>  has been reported to act to some extent as a 5α-reductase inhibitor, similarly to progesterone. Pharmacokinetics Like the closely related progestins hydroxyprogesterone<unk>  and 19-norprogesterone,<unk>  shows poor activity orally and must be administered parenterally; specifically, via intramuscular injection.<unk>  is administered by intramuscular injection, and acts as a long-lasting depot by this route. After an intramuscular injection,<unk>  is completely released from the local depot and is highly bioavailable. A single intramuscular injection of 25 to 50 mg<unk>  in oil solution has been found to have a duration of action of 8 to 13 days in terms of clinical biological effect in the uterus in women. At high doses, the duration of action of<unk>  by intramuscular injection has been found to be at least 21 days. Clinical studies have found<unk>  to be satisfactorily effective as a progestogen when injected once a month, whereas it was poorly effective as an injectable contraceptive when it was injected once every two months. Following a single intramuscular injection of 200 mg radiolabeled<unk>  in 1 mL of solution in men with prostate cancer, maximal levels of<unk>  occurred after 3 ± 1 days and were 420 ± 160 ng/mL. The elimination half-life of<unk>  and its metabolites was 7.5 ± 3.1 days. Approximately 5% of the radioactive steroid content in the blood was unchanged<unk> . No free<unk>  was observed in circulation or in urine.<unk>  and its metabolites were eliminated 72% in feces and 28% in urine. Approximately 48 ± 18% of the injected dose had been eliminated after 14 days and approximately 85 ± 12% of the injected dose had been excreted after 30 days. The metabolism of unesterified<unk>  (17α-hydroxy-19-norprogesterone) is analogous to that of 17α-hydroxyprogesterone, with the corresponding 19-norpregnane metabolites produced.<unk>  has been found to undergo 5α-reduction similarly to progesterone, 17α-hydroxyprogesterone, and<unk> , and at a similar rate as these steroids. Conversely however, due to its<unk>  ester, 5β-reduction of<unk>  is decreased relative to these steroids. As progesterone is metabolized mainly into 5β-pregnanes, decreased 5β-reduction of<unk>  may be involved in its greater potency compared to progesterone. The major metabolites of<unk>  have been reported to be isomers of 19-norpregnanetriol and 19-norpregnanediol-20-one. These metabolites indicate that<unk>  is metabolized mainly by reduction at the C3, C5, and C20 positions. Following an intramuscular injection of 300 mg<unk> , only a slight increase in urinary pregnanetriol excretion has been observed. Cleavage of the<unk>  ester of<unk>  is minimal, which indicates that it is not a prodrug of the unesterified steroid.
Gestonorone caproate
Segesterone acetate
Ingenol mebutate
Nandrolone phenylpropionate
Androstanolone enanthate
Nandrolone furylpropionate
Anagestone acetate
Quingestanol acetate