This drug has no noticeable effect on adrenal corticosteroids biosynthesis. Even when its concentration is over 600 times the concentration required to inhibit aromatase, it still has no noticeable effect the other enzymes in the corticosteroid production pathway.
This drug is absorbed quickly when taken orally and will affect food absorption. Its oral bioavailability is 42%. Postmenopausal women have a higher absorption rate than healthy test subjects. Patients reach peak blood concentration 2-4 hours after intake, and the peak lasts for an average of 1.2 hours, which is 2.9 hours shorter than healthy subjects. It mainly binds to Α1-acid glycoprotein and protein, and its overall binding rate to protein is 90%. It is mainly metabolized by the liver, the metabolite is inactive 17-Hydrecoxetron, and its clearing half-life is 24 hours. It is mostly excreted through urine and feces, which both account for 42% of the consumed amount.
1. This drug cannot be used in combination with estrogen-based drugs to avoid counteracting its medicinal effects.
2. Exemestane is mostly metabolized by CYP3A4, but when used in combination with a strong CYP3A4 inhibitor (Ketoconazole), its pharmacokinetics do not exhibit any change. This is because the inhibitor does not seem to affect the drug’s pharmacokinetics, but it is also possible that the known CYP3A4 inducer lowers the blood concentration of Exemestane.
Indications and Usage
Exemestane is an irreversible steroid aromatase inhibitor. Its structure is similar to that of aromatase’s natural substrate, androstenedione, and acts as a pseudosubstrate. Postmenopausal women’s estrogen is mainly converted from androgen (produced by the adrenal cortex) by aromatase in the surrounding tissue. This drug irreversibly binds with the active site on aromatase to deactivate it, thus dramatically lower estrogen levels in the blood circulation of postmenopausal women. By inhibiting aromatase to lower estrogen levels, it can be used to treat hormone-dependent breast cancer in postmenopausal women.
Exemestane is suitable for treating advanced breast cancer in naturally or artificially postmenopausal women that has not responded well to tamoxifen treatment. It is also suitable for treating estrogen and progesterone receptor positive postmenopausal advanced breast cancer, and it can also be used to treat metastasized breast cancer and as adjuvant therapy for early breast cancer.
1. Not to be used by patients allergic to this drug.
2. Not to be used by pregnant women, breastfeeding women, and children.
Labeled Exemestane, intended for use as an internal standard for the quantification of Exemestane by GC- or LC-mass spectrometry.
For patients resistant to tamoxifen, 25mg of Exemestane, qd, can achieve an objective efficacy rate of 15-28% and a median continuation period of 69-76 weeks. Exemestane is superior to Megestrol, and it can extend the disease progression time. For patients who have worsened conditions following Megestrol treatment, Exemestane can still achieve an objective efficacy rate of 11-13%. A daily 25mg dose of Exemestane has an objective efficacy rate of 6.6% on patients who have not responded to non-steroidal aromatase inhibitors, and the two drugs are not cross-resistant.
Aromasin (Pharmacia& Upjohn).
white to light yellow crystal powder
ChEBI: A 17-oxo steroid that is androsta-1,4-diene-3,17-dione in which the hydrogens at position 6 are replaced by a double bond to a methylene group. A selective inhibitor of the aromatase (oestrogen synthase) system, it is used in the treatment of advanced brea
An antineoplastic (hormonal)
Warnings and precautions
1. Premenopausal women usually do not use Exemestane.
2. Patients with moderate to severe liver or renal failure should use with caution. Exceeding the recommended dosage of Exemestane may increase the occurrence of nonfatal adverse effects.
3. FDA labeled this drug’s pregnancy safety as level D.
4. Elderly patients do not require any special precautions.
Adverse effects include nausea, dryness, constipation, diarrhea, dizziness, insomnia, rash, fatigue, fever, swelling, pain, vomiting, abdominal pain, increased appetite, weight gain, etc. Additionally, some literature reports cases of hypertension, depression, anxiety, difficulty breathing, coughing, etc. There may also be decreases lymph cell amounts, abnormalities in liver function indicators (such as alanine aminotransferase), etc.