Thursday 6 December 2012

Arimidx 1mg by Astra Zeneca

Arimidx 1mg by Astra Zeneca


Product Description
Anastrozole (INN) (marketed under the trade name Arimidex by AstraZeneca) is an aromatase-inhibiting drug approved for treatment of breast cancer after surgery, as well as for metastasis in both pre and post-menopausal women. The severity of breast cancer is increased by estrogen, as sex hormones cause hyperplasia, and differentiation at estrogen receptor sites. Anastrozole works by inhibiting the synthesis of estrogen
Medical uses:
The ATAC (Arimidex, Tamoxifen, Alone or in Combination) trial was an international randomised controlled trial of 9366 women with localized breast cancer who received either anastrozole, tamoxifen, or both for five years, followed by five years of follow-up. After more than 5 years the group that received anastrozole had significantly better clinical results than the tamoxifen group. The trial suggested that anastrozole is the preferred medical therapy for postmenopausal women with localized breast cancer that is estrogen receptor (ER) positive. Another study found that the risk of recurrence was reduced 40%, which also included an increased risk of bone fractures, and that ER negative patients benefited from switching to anastrozole.

Mechanism of action:
Anastrozole binds reversibly to the aromatase enzyme through competitive inhibition, inhibits the conversion of androgens to estrogens in peripheral tissues (outside the CNS), and a few CNS sites in various regions within the brain.

Side effects:
Bone weakness has been associated with anastrozole. Women who switched to anastrozole after two years on tamoxifen reported twice as many fractures as those who continued to take tamoxifen (2.1% compared to 1%). Bisphosphonates are sometimes prescribed to prevent the osteoporosis induced by aromatase inhibitors. The level of circulating oestradiol is likely causal here and not the anastrozole itself, and so the dose will determine likelihood of osteoporosis (oestradiol inhibits osteoclasts, which resorb bone).

Usage in men:
Anastrozole has been tested for reducing estrogens, including estradiol, in men. Excess estradiol in men can cause benign prostatic hyperplasia, gynecomastia, and symptoms of hypogonadism. It can also contribute to increased risk of stroke, heart attack, chronic inflammation, prostate enlargement and prostate cancer. Some athletes and body builders use anastrozole as part of their steroid cycle to reduce and prevent symptoms of excess estrogen--gynecomastia, emotional lability and water retention. Study data suggests dosages of 0.5 mg to 1 mg a day reduce serum estradiol approx. 50% in men, which differs in postmenopausal women.

Usage in children;
Anastrozole may be used off-label in children with precocious puberty, or children with pubertal gynecomastia. Following the onset of puberty, the epiphyseal plate begins to close due to an increased amount of estrogen production escaping local metabolism and spreading to the circulatory system. It is shown to help slow this process, and increase adult height prediction in adolescent males treated with protein-based peptide hormones for the treatment of growth hormone deficiency

Chemical synthesis:
The synthesis begins with nucleophilic substitution of two benzylic bromides in α,α'-dibromomesitylene (prepared by radical bromination of mesitylene, not shown on the scheme) with cyanide by treatment with potassium cyanide under phase transfer conditions, affording the dinitrile. Exhaustive methylation with methyl iodide and sodium hydride leads to the replacement of the more acidic side chain hydrogen atoms by methyl groups. The treatment with bromine in the presence of benzoyl peroxide leads to the formation of the corresponding benzyl bromide. Reaction of that product with 1,2,4-triazole in the presence of a base completes the synthesis of the aromatase inhibitor.

Important information about Arimidex;
Do not use Arimidex if you are pregnant. It could harm the unborn baby.

You may need to take a pregnancy test before using Arimidex, to make sure you are not pregnant.

You should not use Arimidex if you are allergic to anastrozole, if you are breast-feeding a baby, or if you have not yet completed menopause. Arimidex is not for use in men or children.

Before using Arimidex, tell your doctor if you have heart disease, circulation problems, a history of stroke or blood clot, severe liver disease, high cholesterol, osteoporosis, or low bone mineral density.

Arimidex may not work as well if you take it together with tamoxifen or an estrogen medication (such as hormone replacement therapy, estrogen creams, or birth control pills, injections, implants, skin patches, and vaginal rings). Before you start taking this medicine, tell your doctor if you also take tamoxifen or estrogen.

You may need to keep taking Arimidex for up to 5 years. Follow your doctor's instructions.

Before taking Arimidex:
You should not use Arimidex if you are allergic to anastrozole, if you are breast-feeding a baby, or if you have not yet completed menopause. Arimidex is not for use in men or children.

To make sure you can safely take Arimidex, tell your doctor if you have any of these other conditions:

heart disease;

circulation problems;

a history of stroke or blood clot;

severe liver disease;

high cholesterol; or

osteoporosis or low bone mineral density.

Arimidex can decrease bone mineral density, which may increase your risk of developing osteoporosis. Your bone mineral density may need to be tested before and during treatment with this medicine.

FDA pregnancy category D. Do not use Arimidex if you are pregnant. It could harm the unborn baby. Use effective birth control, and tell your doctor if you become pregnant during treatment. It is not known whether anastrozole passes into breast milk or if it could harm a nursing baby. You should not breast-feed while you are using Arimidex.

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