Indication

Treatment of irregular menstruation, functional uterine bleeding, endometriosis; advanced breast cancer and endometrial adenocarcinoma; can also be used as a progesterone component of short-acting combined oral contraceptive tablets. 

Pharmacology and toxicology

This product is a progesterone that has a certain inhibitory effect on the release of pituitary, but is weaker than levonorgestrel and norethisterone. Does not have estrogen and androgen-like activity, but has obvious anti-estrogen effects. Used in combination with estrogen to inhibit ovulation. Animal teratogenicity tests have shown an increase in stillbirth rate and teratogenic effects in rabbits.

Pharmacokinetics

After oral administration, the biological half-life is significantly shorter than levonorgestrel, and most of the metabolites are excreted as glucuronide.

Megestrol is used mainly as an appetite stimulant in a variety of conditions and as an antineoplastic agent in the treatment of breast, endometrial,and prostate cancers. Megestrol has been used extensively in veterinary medicine in the treatment of medical conditions in cats and dogs.Megestrol acts predominantly as a potent agonist of the progesterone receptor to exert its effects.Megestrol is frequently used as an appetite stimulant.