Aromasin - General Information
Aromasin is an oral steroidal aromatase inhibitor used in the adjuvant treatment of hormonally-responsive (also called hormone-receptor-positive, estrogen-responsive) breast cancer in postmenopausal women. It acts as a false substrate for the aromatase enzyme, and is processed to an intermediate that binds irreversibly to the active site of the enzyme causing its inactivation.
Pharmacology of Aromasin
Aromatase is an enzyme that converts hormones to estrogen in the body's adrenal glands. The aromatase inhibitors (AIs) are drugs that reduce estrogen levels by blocking the action of aromatase in the adrenal glands. The selective AIs (SAIs) selectively reduce levels of estrogen without interfering with levels of other steroid hormones that are produced by the adrenal gland. Drugs in this class include anastrozole (Arimidex ™), letrozole (Femara ™) and exemestane (Aromasin ™).
Aromasin for patients
If clinically advisable, patients receiving OxyContin (oxycodone hydrochloride controlled-release) tablets or their caregivers should be given the following information by the physician, nurse, pharmacist, or caregiver:
- Patients should be aware that OxyContin tablets contain oxycodone, which is a morphine-like substance.
- Patients should be advised that OxyContin tablets were designed to work properly only if swallowed whole. OxyContin tablets will release all their contents at once if broken, chewed, or crushed, resulting in a risk of fatal overdose.
- Patients should be advised to report episodes of breakthrough pain and adverse experiences occurring during therapy. Individualization of dosage is essential to make optimal use of this medication.
- Patients should be advised not to adjust the dose of OxyContin without consulting the prescribing professional.
- Patients should be advised that OxyContin may impair mental and/or physical ability required for the performance of potentially hazardous tasks (e.g., driving, operating heavy machinery).
- Patients should not combine OxyContin with alcohol or other central nervous system depressants (sleep aids, tranquilizers) except by the orders of the prescribing physician, because dangerous additive effects may occur, resulting in serious injury or death.
- Women of childbearing potential who become, or are planning to become, pregnant should be advised to consult their physician regarding the effects of analgesics and other drug use during pregnancy on themselves and their unborn child.
- Patients should be advised that OxyContin is a potential drug of abuse. They should protect it from theft, and it should never be given to anyone other than the individual for whom it was prescribed.
- Patients should be advised that they may pass empty matrix "ghosts" (tablets) via colostomy or in the stool, and that this is of no concern since the active medication has already been absorbed.
- Patients should be advised that if they have been receiving treatment with OxyContin for more than a few weeks and cessation of therapy is indicated, it may be appropriate to taper the OxyContin dose, rather than abruptly discontinue it, due to the risk of precipitating withdrawal symptoms. Their physician can provide a dose schedule to accomplish a gradual discontinuation of the medication.
- Patients should be instructed to keep OxyContin in a secure place out of the reach of children. When OxyContin is no longer needed, the unused tablets should be destroyed by flushing down the toilet.
Exemestane is extensively metabolized by CYP 3A4, but coadministration of ketoconazole, a potent inhibitor of CYP 3A4, has no significant effect on exemestane pharmacokinetics. Significant pharmacokinetic interactions mediated by inhibition of CYP isoenzymes therefore appear unlikely. Co-medications that induce CYP 3A4 (e.g., rifampicin, phenytoin, carbamazepine, phenobarbital, or St. Johnís wort) may significantly decrease exposure to exemestane. Dose modification is recommended for patients who are also receiving a potent CYP 3A4 inducer.
Drug/Laboratory Tests Interactions
No clinically relevant changes in the results of clinical laboratory tests have been observed.
AROMASIN Tablets are contraindicated in patients with a known hypersensitivity to the drug or to any of the excipients.
Additional information about Aromasin
Aromasin Indication: For the treatment of advanced breast cancer in postmenopausal women whose disease has progressed following tamoxifen therapy.
Mechanism Of Action: Breast cancer cell growth may be estrogen-dependent. Aromatase (exemestane) is the principal enzyme that converts androgens to estrogens both in pre- and postmenopausal women. While the main source of estrogen (primarily estradiol) is the ovary in premenopausal women, the principal source of circulating estrogens in postmenopausal women is from conversion of adrenal and ovarian androgens (androstenedione and testosterone) to estrogens (estrone and estradiol) by the aromatase enzyme in peripheral tissues. Estrogen deprivation through aromatase inhibition is an effective and selective treatment for some postmenopausal patients with hormone-dependent breast cancer. Aromasin is an irreversible, steroidal aromatase inactivator, structurally related to the natural substrate androstenedione. It acts as a false substrate for the aromatase enzyme, and is processed to an intermediate that binds irreversibly to the active site of the enzyme causing its inactivation, an effect also known as "suicide inhibition". Aromasin significantly lowers circulating estrogen concentrations in postmenopausal women, but has no detectable effect on adrenal biosynthesis of corticosteroids or aldosterone. Aromasin has no effect on other enzymes involved in the steroidogenic pathway up to a concentration at least 600 times higher than that inhibiting the aromatase enzyme.
Drug Interactions: Not Available
Food Interactions: Not Available
Generic Name: Exemestane
Synonyms: Exemestano [Inn-Spanish]; Exemestanum [Inn-Latin]
Drug Category: Antineoplastic Agents
Drug Type: Small Molecule; Approved
Other Brand Names containing Exemestane: Aromasin; Exemestance;
Toxicity (Overdose): Convulsions
Protein Binding: 90%
Half Life: 24 hours
Dosage Forms of Aromasin: Tablet Oral
Chemical IUPAC Name: (8R,9S,10R,13S,14S)-10,13-dimethyl-6-methylidene-7,8,9,11,12,14,15,16-octahydrocyclopenta[a]phenanthrene-3,17-dione
Chemical Formula: C20H24O2
Exemestane on Wikipedia: http://en.wikipedia.org/wiki/Exemestane
Organisms Affected: Humans and other mammals