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
A single 4 mg intramuscular injection of estradiol cypionate or estradiol valerate has been found to result in maximal plasma levels of estradiol of about 250 pg/mL and 390 pg/mL, respectively, with levels declining to 100 pg/mL (the baseline for estradiol cypionate) by 12 to 14 days. A single 2.5 mg intramuscular injection of estradiol benzoate in patients being administered a GnRH analogue (and hence having minimal baseline levels of estrogen) was found to result in serum estradiol levels of >400 pg/mL at 24 hours post-administration. The differences in the serum levels of estradiol achieved with these different estradiol esters may be explained by their different rates of absorption, as their durations and levels attained appear to be inversely proportional. For instance, estradiol benzoate, which has the shortest duration (4 to 5 days with a single intramuscular injection of 5 mg), produces the highest levels of estradiol, while estradiol cypionate, which has the longest duration (~11 days with 5 mg), produces the lowest levels of estradiol. Estradiol valerate was found to have a duration of 7 to 8 days after a single intramuscular injection of 5 mg.