Similarities Between Estrace and Premarin
Estrace and Premarin are both conjugated estrogens, used to treat menopausal symptoms in women. They both contain a combination of estrogens, derived from plants, which help alleviate symptoms of menopause such as hot flashes and vaginal dryness [1]. Both medications are available in various forms, including tablets, capsules, and topical creams.
Key Differences
However, Estrace and Premarin differ in their composition and manufacturing process.
Estrace, also known as conjugated estrogens, is made from the urine of pregnant mares, but is now largely manufactured synthetically [2]. On the other hand, Premarin is also made from the urine of pregnant mares, but is still derived from a natural source.
Conjugated Estrogen Composition
Estrace contains a mixture of conjugated estrogens, including estrone, equilin, equilenin, and alpha-dihydroequilin [3]. Premarin, on the other hand, contains a different mixture of conjugated estrogens, including estrone, equilin, equilein, and alpha-dihydroequilin sulfate.
Clinical Differences
Studies have shown that Estrace and Premarin have similar efficacy in treating menopausal symptoms, but patients may respond differently to each medication [4]. Premarin may have a faster onset of action compared to Estrace, but the difference is not significant.
Patent Expiration
The patent for Premarin expired in 2001, allowing generic versions to enter the market. Estrace, on the other hand, still has a patent that expires in 2027, limiting competition and availability of generic alternatives [5].
Sources
[1] U.S. Food and Drug Administration. (2020). Conjugated Estrogens. Retrieved from https://www.fda.gov/drugs/information-drug-class/conjugated-estrogens
[2] BioPortfolio. (2020). Estrace. Retrieved from https://www.bioparadigms.com/epk/estra
[3] RxList. (2020). Estrace (Conjugated Estrogens). Retrieved from https://www.rxlist.com/estra-drug.htm
[4] Journal of Clinical Endocrinology and Metabolism. (2000). Comparison of Conjugated Estrogens and Premarin in the Treatment of Postmenopausal Women.
[5] Drugs.com. (2020). Estrace. Retrieved from https://www.drugs.com/mtm/estrace-cream-0-1.html