Conjugated equine estrogen

Conjugated estrogens

Estrone sulfate, the primary active agent of conjugated estrogen products.
Combination of
Sodium estrone sulfate	Estrogen
Sodium equilin sulfate	Estrogen
Sodium equilenin sulfate	Estrogen
Clinical data
Trade names	Cenestin, Enjuvia, Congest, C.E.S., Prempro (with MPA), Premphase (with MPA)
Synonyms	Conjugated equine estrogens; CEEs
Routes of administration	By mouth
Drug class	Estrogen

Conjugated estrogens, or conjugated equine estrogens (CEEs), are an estrogen product that contain blended equine estrogens including estrone sulfate, equilin sulfate, and equilenin sulfate. CEEs are used clinically in menopausal hormone therapy, with marketed products including both natural preparations isolated from the urine of pregnant mares (brand names Premarin) as well as fully synthetic replications of the natural preparations (brand names Cenestin, Enjuvia, Congest, and C.E.S.).Prempro and Premphase are combination formulations of natural CEEs with medroxyprogesterone acetate.

The exact composition of Premarin specifically is as follows: sodium estrone sulfate (49.3%), sodium equilin sulfate (22.4%), sodium 17α-dihydroequilin sulfate (13.8%), sodium 17α-estradiol sulfate (4.5%), sodium 8,9-dehydroestrone sulfate (3.5%), sodium equilenin sulfate (2.2%), sodium 17β-dihydroequilin sulfate (1.7%), sodium 17α-dihydroequilenin sulfate (1.2%), sodium 17β-estradiol sulfate (0.9%), sodium 17β-dihydroequilenin sulfate (0.5%), and sodium 8,9-dehydroestradiol sulfate (small amounts), as well as hippulin (also small amounts).