Estradiol enantate
Estradiol enantate, sold under the brand names Perlutal and Topasel among others, is an estrogen medication which is used in hormonal birth control. It is formulated in combination with dihydroxyprogesterone acetophenide (DHPA; algestone acetophenide), a progestin, and is used as a combined injectable contraceptive. Estradiol enantate is not available alone. The medication is given by injection into muscle once a month.
Side effects of estradiol enantate include breast tenderness, breast enlargement, nausea, headache, and fluid retention. The drug is a synthetic estrogen and hence is an agonist of the estrogen receptor (ER), the biological target of estrogens like estradiol. Estradiol enantate is an estrogen ester and a long-lasting prodrug of estradiol in the body. Because of this, it is considered to be a natural and bioidentical form of estrogen.
Estradiol enantate was first described by 1954, and was first studied in combination with DHPA as a combined injectable contraceptive in 1964. The combination was introduced for clinical use by the mid-1970s. Estradiol enantate is not available as a standalone medication (i.e., by itself without DHPA). The combination is available in Latin America and Hong Kong, and was also previously marketed in Spain and Portugal.
Bioidentical hormone replacement therapy
Estriol was part of the United States Pharmacopeia before FDA approval was needed for its use. Its approval was grandfathered in by the FDA until 2008 when the agency banned its use, stating that manufacturers of estriol would have to create a new application and estriol would be treated as a new drug. Its use is not approved by Health Canada; estriol is not available as a pharmaceutical preparation in Canada or the United States, but is a commonly prescribed conventional treatment in other countries and is available as a cream or vaginal suppository in the United Kingdom and the European Union. Estradiol is available as brand-name products in both oral and transdermal forms.