Natural and synthetic estrogen

Natural and synthetic estrogen

Estrogens that treat endocrine system disorders include:

• natural products, such as conjugated estrogenic substances, estradiol, and estropipate

• synthetic estrogens, such as esterified estrogens,estradiol cypionate, estradiol valerate, and ethinylestradiol.

Pharmacokinetics

Estrogens are well absorbed and distributed throughout the body. Metabolism occurs in the liver, and the metabolites are excreted primarily by the kidneys.

Pharmacodynamics

The exact mechanism of action of estrogen isn’t clearly under-stood, but it’s believed to increase synthesis of deoxyribonucleic acid, ribonucleic acid, and protein in estrogen-responsive tissues in the female breast, urinary tract, and genital organs.

Pharmacotherapeutics

Estrogens are prescribed:

·                 primarily for hormone replacement therapy in postmenopausal women to relieve symptoms caused by loss of ovarian function (see Hormone replacement therapy and heart disease)

·                 less commonly for hormonal replacement therapy in women with primary ovarian failure or female hypogonadism (reduced hormonal secretion by the ovaries), for prevention and treatment of osteoporosis in postmenopausal women, and in patients who have undergone surgical castration

·                 palliatively to treat advanced, inoperable breast cancer in post-menopausal women and prostate cancer in men.

Drug interactions

Relatively few drugs interact with estrogens:

§    Estrogens may decrease the effects of anticoagulants, increas-ing the risk of blood clots.

§    Antibiotics, barbiturates, carbamazepine, phenytoin, primidone, and rifampin reduce estrogen effectiveness.

§    Estrogens interfere with the absorption of dietary folic acid, which may result in a folic acid deficiency. (See Adverse reactionsto estrogens.)