However, doses of 1 to 5 mg MGA were previously used in combined birth control pills in combination with the estrogen ethinylestradiol or mestranol. MGA is an effective contraceptive by itself at dosages of 0.35 to 0.5 mg/day, but is not effective at a dosage of 0.25 mg/day. MGA alone does not inhibit ovulation at a dosage of 0.5 mg/day, nor does it fully inhibit ovulation at a dosage of 0.7 mg/day or even at a dosage of 5 mg/day. The combination of 2 to 5 mg/day MGA and 100 μg/day mestranol has been found to consistently inhibit ovulation, whereas either medication alone did not completely inhibit ovulation in all women.Suppression of testosterone levels by MGA is responsible for its effectiveness in the treatment of conditions like prostate cancer and benign prostatic hyperplasia. In one study, 120 to 160 mg/day MGA suppressed testosterone levels in men by 72%. However, a recovery or "escape" of testosterone levels, gradually returning to near-normal values, has been observed in most men after 2 to 6 months of MGA therapy, and this has limited the usefulness of the medication. The combination of a lower dosage of MGA (40–80 mg/day) and a low oral dosage of an estrogen such as estradiol (0.5–1.5 mg/day), diethylstilbestrol (0.1–0.2 mg/day) or ethinylestradiol (50 µg/day) is able to suppress testosterone levels into the castrate range in men, maintain this suppression long-term, and achieve equivalent effectiveness to high-dosage estrogen monotherapy in the treatment of prostate cancer with comparatively greatly reduced toxicity and side effects.
The lawsuit claimed that Par marketed the product as effective for this use, despite having conducted no well-controlled studies to support a claim of greater efficacy for Megace ES, and prior knowledge of the severe adverse side effects for geriatric patients, including deep vein thrombosis, toxic reactions with impaired renal function, and mortality. Society and culture
Generic names
Megestrol acetate is the generic name of the drug and its INNM, USAN, USP, and BANM, while megestrol is the INN and BAN and mégestrol the DCF of megestrol, the free alcohol form of MGA. The medication is also known by its developmental code names BDH-1298, NSC-71423, and SC-10363. Brand names
MGA is marketed under a variety of brand names throughout the world but is most commonly sold under the brand name Megace. It is also available under the brand name Megace ES in the United States and under the brand name Megace OS in Canada. For use in veterinary medicine, MGA is sold as Ovaban in the United States and as Ovarid in the United Kingdom. Availability
MGA is available widely throughout the world, including in the United States, Canada, the United Kingdom, Ireland, elsewhere throughout Europe, Australia, New Zealand, Latin America, Asia, and a few African countries. It does not appear to be marketed in Germany, Russia, South Africa, Japan, India, or Mexico, among other countries. Generation
Progestins in birth control pills are sometimes grouped by generation.