Estradiol (medication)
Estradiol is also widely available in combination with progestogens. It is available in combination with norethisterone acetate under the major brand names Activelle, Cliane, Estalis, Eviana, Evorel Conti, Evorel Sequi, Kliogest, Novofem, Sequidot, and Trisequens; with drospirenone as Angeliq; with dydrogesterone as Femoston, Femoston Conti; and with nomegestrol acetate as Zoely. Estradiol valerate is available with cyproterone acetate as Climen; with dienogest as Climodien and Qlaira; with norgestrel as Cyclo-Progynova and Progyluton; with levonorgestrel as Klimonorm; with medroxyprogesterone acetate as Divina and Indivina; and with norethisterone enantate as Mesigyna and Mesygest. Estradiol cypionate is available with medroxyprogesterone acetate as Cyclo-Provera, Cyclofem, Feminena, Lunelle, and Novafem; estradiol enantate with algestone acetophenide as Deladroxate and Topasel; and estradiol benzoate is marketed with progesterone as Mestrolar and Nomestrol.
Pharmacokinetics of estradiol
Estradiol is well-absorbed regardless of route of administration. However, the bioavailability of estradiol differs substantially with different routes of administration. Oral estradiol has an average bioavailability of around 5%, requiring relatively high dosages of estradiol for effects. Conversely, transdermal estradiol has much higher potency, with a 20-fold lower dosage of transdermal estradiol being equivalent in potency to oral estradiol. Estradiol administered in the form of an ester by intramuscular or subcutaneous injection has complete bioavailability.