This results in an increased risk of blood clots and cardiovascular problems with CEEs relative to estradiol.Premarin, the major brand of CEEs in use, is manufactured by Pfizer and was first marketed in 1941 in Canada and in 1942 in the United States. It is the most commonly used form of estrogen in menopausal hormone therapy in the United States. However, it has begun to fall out of favor relative to bioidentical estradiol, which is the most widely used form of estrogen in Europe for menopausal hormone therapy. CEEs are available widely throughout the world. An estrogen preparation very similar to CEEs but differing in source and composition is esterified estrogens. In 2017, it was the 206th most commonly prescribed medication in the United States, with more than two million prescriptions. Medical uses
CEEs are a form of hormone therapy used in women. It is used most commonly in postmenopausal women who have had a hysterectomy to treat hot flashes, and burning, itching, and dryness of the vagina and surrounding areas. It must be used in combination with a progestogen in women who have not had a hysterectomy. For women already taking the medication, it can be used to treat osteoporosis, although it is not recommended solely for this use. Some lesser known uses are as a means of high-dose estrogen therapy in the treatment of breast cancer in both women and men and in the treatment of prostate cancer in men.
Animal welfare
Animal welfare groups claim that animal husbandry and urine collection methods used in the production of CEEs cause undue stress and suffering to the mares involved. Animal activists have made claims of abuses ranging from inadequate stall size, long periods of confinement, cumbersome urine collection, and continuous breeding cycles. After reaching advanced age, many of the mares are adopted for recreation use, while some are sent to feed lots for slaughter. Despite the controversy, the USDA called the CEEs HRT industry a model of self-regulation. See also
Conjugated estrogens/medroxyprogesterone acetate
Conjugated estrogens/norgestrel
Conjugated estrogens/methyltestosterone
Bazedoxifene/conjugated estrogens
Estrogenic substances
Conjugated estriol
List of combined sex-hormonal preparations

Notes
References
Further reading
Bhavnani, Bhagu R. (1988). "The Saga of the Ring B Unsaturated Equine Estrogens*". Endocrine Reviews. 9 (4): 396–416. doi:10.1210/edrv-9-4-396. ISSN 0163-769X. PMID 3065072. Ansbacher R (April 1993). "Bioequivalence of conjugated estrogen products". Clin Pharmacokinet. 24 (4): 271–4. doi:10.2165/00003088-199324040-00001. PMID 8387902. S2CID 7681617. OConnell MB (September 1995). "Pharmacokinetic and pharmacologic variation between different estrogen products". J Clin Pharmacol. 35 (9 Suppl): 18S–24S. doi:10.1002/j.1552-4604.1995.tb04143.x. PMID 8530713. S2CID 10159196. Egarter C, Geurts P, Boschitsch E, Speiser P, Huber J (April 1996). "The effects of estradiol valerate plus medroxyprogesterone acetate and conjugated estrogens plus medrogestone on climacteric symptoms and metabolic variables in perimenopausal women". Acta Obstet Gynecol Scand. 75 (4): 386–93. doi:10.3109/00016349609033337. PMID 8638462. S2CID 44498140. Bhavnani BR (January 1998). "Pharmacokinetics and pharmacodynamics of conjugated equine estrogens: chemistry and metabolism". Proc. Soc. Exp. Biol. Med. 217 (1): 6–16. doi:10.3181/00379727-217-44199. PMID 9421201. S2CID 45177839. Gruber DM, Huber JC (December 1999). "Conjugated estrogens--the natural SERMs". Gynecol. Endocrinol. 13 Suppl 6: 9–12. PMID 10862263.