1 What is Arimidex?

Brand: Arimidex

Generic: Anastrozole

Anastrozole is an orally active non-steroidal compound that reversibly inhibits aromatization all over the body, including that within the breast cancer cells, resulting in nearly total estrogen deprivation. Proliferation of estrogen dependent breast carcinoma cells is suppressed to a greater extent than with tamoxifen.

In addition, it is useful as adjuvant therapy in early ER-positive breast cancer as well as for palliation of advanced cases in postmenopausal women. In early cases, tumor recurrence time was found to be longer than with tamoxifen. Risk of new tumor appearing in the contralateral breast was also lower with anastrozole. Further, many tamoxifen resistant cases responded with increased survival.

This medicine is available in tablet form only with your doctor's prescription.

Randomized clinical trials have established its utility in:

  • Early breast cancer: It is a first line drug for adjuvant therapy after mastectomy in ER-positive postmenopausal women. Extended adjuvant therapy with anastrozole beyond the standard 5 year tamoxifen treatment continues to afford protection, whereas continuation of tamoxifen is not useful. Replacement of tamoxifen by an aromatase inhibitor (e.g. anastrozole) is now recommended after 2 years (sequential therapy). Survival is prolonged in patients who have positive axillary lymph nodes.
  • Advanced breast cancer: Current guidelines recommend anastrozole as first line therapy because of longer time to disease progression and higher response rate obtained with it compared to tamoxifen.

2 What to Know Before Using

If you are about to start Arimidex therapy, the risk-benefit ratio of taking the drug should be considered carefully. Indeed, the suitable drug therapy is chosen with active participation of both the doctor and the patient.

There are some important factors such as drug interactions, metabolic impairment, hypersensitivity reaction, pregnancy, lactation etc. which may alter the desired therapeutic effects of such medications.

Sometimes the presence of other health disorders affects the beneficial effects of this medicine and even may cause serious toxic effects. If you have had any allergic reactions to any medicine, you must inform your doctor about that.

Make sure you mention your doctor if you have any other health problems or medical disorders.

Further, the use of anastrozole is contraindicated in:

  • Patients with known hypersensitivity to anastrozole
  • Premenopausal women
  • Osteoporosis
  • Hypercholesterolemia (increased cholesterol level in blood)
  • Ischemic heart disease (e.g. myocardial infarction, angina)
  • Hepatic impairments (e.g. liver cirrhosis)

Moreover, certain drugs should not be used concurrently with such medications. It is always recommended to consult with your doctor if you are in need of some other medications or even any over-the-counter medicine for another health problem in order to avoid unwanted toxic effects. However, concurrent tamoxifen therapy as well as oestrogen-containing therapies should be avoided as they may diminish its pharmacological action.

However, studies performed in pregnant women with anastrozole have demonstrated a risk to the fetus.

Thus, this medicine should not be used during pregnancy because the risk clearly outweighs any possible benefit.

3 Proper Usage

The dosage schedule and the duration of drug therapy depend on the particular medical problem for which you are using this medicine. The therapeutic dose may also vary with patient’s condition or requirement and the strength of the medicine as well.

You should use this medicine following the directions given by your doctor.

Since this drug accumulates in the body to produce peak effect even after 7-10 days, it is suitable for single daily dosing. For the treatment of breast cancer, the usual dose in an adult is 1 mg once a day. In case of children, the therapeutic dose must be determined by a pediatrician.

If you miss any dose of this medicine, you should take it as soon as possible. But if it is time for your next dose, then you should skip the missed dose and go back to your regular treatment schedule.

Further, it is advised to store the medicine in a closed container at room temperature away from heat, moisture, and direct light. All kinds of medicines should be kept out of the reach of children as well as outdated medicines should be disposed by an appropriate way.

4 Precautions to Take

Following guidelines should be followed while you are using such medications:

  • Firstly, regular visits to your doctor are recommended to check that this medicine is working properly or not. Sometimes blood tests may be needed to check for unwanted effects.
  • Anastrozole should not be used in premenopausal women. That’s why the menopause should be defined biochemically if there is doubt about menopausal status.
  • As anastrozole lowers circulating estrogen levels, it may cause a reduction in bone mineral density with a possible consequent increased risk of fracture. Thus, the bone mineral density should be assessed at the commencement of treatment and at regular intervals thereafter.
  • Administration of anastrozole in patients with moderate and severe hepatic and/or renal impairment should be performed cautiously.
  • You should know that using this medicine during pregnancy can harm your unborn baby. That why, you should use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using the medicine, tell your doctor right away.
  • The use of anastrozole is not recommended for use in children and adolescents as safety and efficacy have not been established in this group of patients.

5 Potential Side Effects

Although each drug comes with little or more side effects, but most of the time remain subtle. Usual side effects need no medical attention because these side-effects usually go away during the treatment episode as your body adjusts to the medicine. In addition, your doctor may advise you about the ways how to prevent or reduce those unwanted side-effects.

You may need to consult with the doctor if you have developed

  • itching,
  • hives,
  • hoarseness,
  • espiratory distress,
  • chest pain,
  • difficulty in swallowing,
  • any swelling of your hands, face, or mouth while you are using this medicine.

However, you may need to consult with your doctor when the following problems become significant:

  • Common side effects are hot flushes, vaginal dryness, vaginal bleeding, nausea, diarrhea, and thinning of hair.
  • This medicine may increase your blood cholesterol level. If this happens, you may need to take certain medicines to lower the cholesterol.
  • Arthralgia and acceleration of osteoporosis are prominent. However, it does not predispose to endometrial carcinoma or to venous thromboembolism.
  • Moreover, this drug may accelerate bone loss, predisposing to fractures, and arthritic symptoms.

6 Related Clinical Trials