這個機轉可以解釋為何exemestane停藥一段時間,體內雌激素的濃度仍然很低的原因。
Absorption
Rapidly absorbed. At least 42% if the dose is absorbed. T max is 1.2 h (women with breast cancer) and 2.9 h (healthy women). When taken after a high-fat breakfast, the plasma levels increased approximately 40%.
Distribution
90% protein bound.
Metabolism
Extensively metabolized. CYP3A4 is the principal isoenzyme involved in the oxidation of exemestane. The metabolites are inactive or inhibit aromatase with decreased potency compared to exemestane.
Elimination
The t 1/2 is 24 h. Approximately 42% is excreted in the urine and approximately 42% is excreted in the feces. Less than 1% is excreted unchanged in the urine.
Special Populations
Renal Function Impairment
AUC is about 3 times higher in those with moderate or severe renal insufficiency. No dosage adjustment necessary.
Hepatic Function Impairment
AUC increased approximately 3 times in those with moderate or sever hepatic insufficiency. No dosage adjustment necessary.
A possible decrease of exemestane by agents which inhibit or induce CYP-450 3A4 (eg, rifampin, phenobarbital, erythromycin, ketoconazole).
2.運動員慎用。
1.限停經後或卵巢切除後,且女性荷爾蒙受體 (estrogen receptor) 陽性之晚期乳癌病患,經使用tamoxifen 無效後,方可使用。
2.具有雌激素受體陽性之停經婦女,使用tamoxifen 至少兩年之高危險早期侵犯性乳癌的輔助治療,且不得與tamoxifen 或其他aromatase inhibitor 併用。使用時需同時符合下列規定:(105/8/1)
(1)病歷上應詳細記載手術資料、病理報告(應包含ER、PR 之檢測結果且無復發現象)。
(2)本案藥品使用不得超過三年。




