sodium 13-methyl-17-oxo-3-sulfonatooxy-7,8,9,11,12,14,15,16-octahydro-6H-cyclopenta[ a] phenanthrene

Absorption
Well absorbed from GI tract. The tablets slowly release the drug over several hours.

Distribution
Bound to sex hormone–binding globulin and albumin. Widely distributed and generally found in higher concentration in the sex hormone target organs. Crosses the placenta.

Metabolism
Partially metabolized by CYP3A4. Metabolized in the liver and undergoes enterohepatic recirculation. Estradiol is converted reversibly to estrone, and both can be converted to estriol (major urinary metabolite).

Elimination
Estradiol, estrone, and estriol are excreted in the urine along with glucuronide and sulfate conjugates.

Corticosteroids (eg, prednisone)
Increased pharmacologic and toxicologic effects of corticosteroids may occur.

Hydantoins (eg, phenytoin)
Loss of seizure control or decreased estrogenic effects may occur.

Inducers of CYP3A4 (eg, barbiturates [eg, phenobarbital], bosentan, carbamazepine, modafinil, rifampin, St. John's wort, topiramate)
May reduce plasma estrogens, resulting in a decrease in therapeutic effects and changes in uterine bleeding profile.

Inhibitors of CYP3A4 (eg, azole antifungal agents [eg, itraconazole, ketoconazole], grapefruit juice, macrolide antibiotics [eg, clarithromycin, erythromycin], ritonavir)
May elevate estrogen plasma levels, resulting in increased adverse reactions.

Thyroid hormones (eg, levothyroxine)
Serum free thyroxine concentrations may be decreased, increasing serum thyrotropin concentrations and the need for thyroid hormone.

有下列情形的婦女不可使用：
(1) 已知或懷疑懷孕者。
(2) 未經診斷之不正常生殖道出血者。
(3) 已知，懷疑或過去罹患乳癌者。
(4) 已知或懷疑罹患與雌激素有關之惡性腫瘤者（例如子宮內膜癌、子宮內膜增生）。
(5) 罹患或曾罹患靜脈血栓性栓塞（例如深層靜脈栓塞、肺栓塞）。
(6) 罹患或最近罹患動脈栓塞疾病（例如中風、心肌梗塞）。
(7) 患有肝臟功能不全或疾病者（當肝功能無法回復正常者）。
(8) 對於會引起過敏反應之病患也不可使用。

使用本品考慮到與口服雌激素治療有關的警語、注意事項及不良反應。