EstradiolDose, contraindications and adverse effects for Horses.

Natural estrogen hormone; used in reproductive management protocols and historically for postbreeding mismating prevention. Estradiol is used to enhance estrus behavior and receptivity in non-cycling or ovariectomized mares and to hasten the onset of ovulation in transitional mares. It is also used in mares to synchronize estrus (when used in combination with progesterone), to induce lactation (when used in combination with domperidone), and to treat placen- titis and estrogen-responsive urinary incontinence. Histor

Estradiol is the most active endogenous estrogen. Estrogens are necessary for the normal growth and development of female sex organs and, in some species, contribute to the development and maintenance of secondary female sex characteristics.

Estradiol is contraindicated in patients hypersensitive to the drug formulation and during pregnancy, as it can cause fetal malformations of the genitourinary system and induce bone marrow depression in the fetus. In humans, the drug is contraindicated in patients with abnormal genital bleeding of unknown etiology, breast cancer or estrogen-dependent neoplasia, hepatic dysfunction or disease, or with a history of arterial or deep vein thrombosis or pulmonary embolism.

Estrogens have been associated with severe adverse effects in small animals. In cats and dogs, estrogens are considered toxic to the bone marrow and can cause blood dyscrasias. Blood dyscrasias are more prevalent in older animals and when higher dosages are used. Initial- ly, a thrombocytosis and/or leukocytosis may be noted, but thrombocytopenia and leukopenia will gradually develop.

When therapy is chronic or used at high doses, perform baseline and periodic (eg, monthly): ■ CBC: The frequency of monitoring with chronic therapy depends on the underlying clinical presentation. ■ Hepatic enzymes (eg, ALT, AST, ALP)