Analysis of information sources in references of the Wikipedia article "Megestrol acetate" in English language version.
Several foreign countries, including Germany, Canada, and Great Britain, have banned the sale of birth control pills containing megestrol acetate after a study done at FDA's request indicated it caused breast cancer in dogs. Megestrol acetate has never been marketed in the United States as an oral contraceptive. FDA routinely requires long-term animal studies before any drug can be marketed for human use. Following animal studies with megestrol acetate, FDA in the late sixties and early seventies allowed limited studies of the drug in women. In 1972, after noticing a significant number of test dogs developing breast nodules (none of them malignant), FDA ordered that megestrol acetate be discontinued in human oral contraceptive studies.
Megestrol was never marketed in the United States for contraceptive use because in 1972, FDA took prompt action to discontinue investigational studies on megestrol after dogs exposed to the drug for four years In a chronic toxicity study developed benign breast tumors.
17α-Hydroxyprogesterone caproate is a depot progestogen which is entirely free of side actions. The dose required to induce secretory changes in primed endometrium is about 250 mg. per menstrual cycle.
Specific actions of neurosteroids on ion transport across the neuronal plasma membrane have been described (see Fig. 2[10). In hippocampal CA1 neurons, Ffrench Mullen et al. (76) observed an inhibition by PREG, PREGS, and 3α,5β-TH PROG (but not PROG) of both the N- and L-type calcium channel currents, mediated by a pertussis toxin-sensitive G protein mechanism, associated with the activation of protein kinase C. PROG still has no effect on calcium channels of hypothalamic neurons from the ventromedial nucleus; however, the synthetic progestin megestrol acetate inhibits some high-threshold Ca2+ channel currents: not the N-type nor the P-type Ca2+ channel currents, but the residual current. Appetite enhancement induced by megestrol acetate might be partly due to the inhibition of these Ca2+ channel currents, and the attenuation of the firing of ventromedial nucleus neurons, involved in satiety mechanisms (77).
Each Delpregnin tablet contains 5 mg megestrol acetate + 0.1 mg mestranol.
Your Q & A concerning megestrol acetate (Oct MVP, p 27), a product containing this compound (Ovarid: Glaxo) has been commercially available for controlling estrus in bitches in the UK for nearly 2 years.
In England, where megestrol acetate has been marketed for eight years, it is recommended to treat false pregnancy and estrogen-dependent mammary tumors in dogs. It has also been used successfully to treat hypersexuality in male dogs, and miliary dermatitis and eosinophilic granulomas in cats. In 1974, megestrol acetate was approved in the United States for postponement of es- trus and treatment of false pregnancy in dogs.
In 1974, Sobering marketed megestrol acetate3 (Figure 1) under the trade name of Ovaban® (Ovarid® in Europe).
A radioimmunoassay (RIA), radioligand assay and equilibrium dialysis for determination of plasma and salivary megestrol acetate (MA) concentration, sex hormone binding globulin (SHBG) capacity in plasma and percentage albumin bound MA were studied in healthy women receiving single im injection of estradiol-megestrol long-acting injectable contraceptive. The results showed that after injection the concentration of plasma MA increased rapidly. The meantime of peak plasma MA level was 3rd day, there was a linear relationship between log of plasma MA concentration and time (day) after administration in all subjects, elimination phase half-life t1/2β = 14.35 ± 9.1 days. The plasma sex hormone-binding globulin capacity significantly increased at 7th, 14th day and decreased at 21st, 29th day after injection. The percentage albumin bound MA was 82.4%. There was no specific sex hormone-binding globulin bound MA. There was a positive correlation between the MA concentrations in saliva and those in plasma.
The results showed that after injection the concentration of plasma MA increased rapidly. The meantime of peak plasma MA level was 3rd day, there was a linear relationship between log of plasma MA concentration and time (day) after administration in all subjects, elimination phase half-life t1/2β = 14.35 ± 9.1 days.
Doses [of megestrol acetate] of as high as 1,600 mg/d, given in divided doses three or four times daily, have been given with no clear increase in side effects except for weight gain, mild increases in blood pressure (BP), and some fluid retention.45
Doses [of megestrol acetate] of as high as 1,600 mg/d, given in divided doses three or four times daily, have been given with no clear increase in side effects except for weight gain, mild increases in blood pressure (BP), and some fluid retention.45
A radioimmunoassay (RIA), radioligand assay and equilibrium dialysis for determination of plasma and salivary megestrol acetate (MA) concentration, sex hormone binding globulin (SHBG) capacity in plasma and percentage albumin bound MA were studied in healthy women receiving single im injection of estradiol-megestrol long-acting injectable contraceptive. The results showed that after injection the concentration of plasma MA increased rapidly. The meantime of peak plasma MA level was 3rd day, there was a linear relationship between log of plasma MA concentration and time (day) after administration in all subjects, elimination phase half-life t1/2β = 14.35 ± 9.1 days. The plasma sex hormone-binding globulin capacity significantly increased at 7th, 14th day and decreased at 21st, 29th day after injection. The percentage albumin bound MA was 82.4%. There was no specific sex hormone-binding globulin bound MA. There was a positive correlation between the MA concentrations in saliva and those in plasma.
Doses [of megestrol acetate] of as high as 1,600 mg/d, given in divided doses three or four times daily, have been given with no clear increase in side effects except for weight gain, mild increases in blood pressure (BP), and some fluid retention.45