Understanding Arimidex: A Helping Hand For Breast Cancer

An Effective Weapon Against Recurrence

Arimidex is a prescription tablet taken once a day by mouth to treat hormone receptor-positive breast cancer in postmenopausal women. The active ingredient, anastrozole, is an aromatase inhibitor. It works by blocking the enzyme aromatase from producing estrogen in the body. This starves many breast cancers of the estrogen fuel they need to grow and spread.

By limiting estrogen, Arimidex can:

  • Reduce the risk of breast cancer coming back after surgery
  • Slow or stop the progress of advanced breast cancer
  • Shrink or stabilize tumors when cancer has spread

In multiple major clinical trials against other hormonal therapies like tamoxifen, using Arimidex for 5 years after surgery, either alone or following 2-3 years of tamoxifen, lowered the risk of recurrence, second breast cancers in the other breast, and death.

Approved Uses For Fighting Breast Cancer

The Food and Drug Administration (FDA) has approved Arimidex for these uses related to treating hormone receptor-positive (HR+) breast cancer:

As Additional Protection After Surgery

  • Adjuvant treatment for early stage HR+ cancer in postmenopausal women, given for 5 years after surgery, chemotherapy, or radiation, to reduce the risk of the cancer returning.

Research shows the risk of recurrence drops around 40% when taking Arimidex for 5 years versus no additional treatment.

As A Weapon Against Advanced Breast Cancer

  • First-line treatment for advanced HR+ breast cancer that has spread outside the breast to other organs like bones, liver or lungs (metastatic cancer) or is locally advanced.
  • Treatment for HR+ cancer that has recurred or spread further, after previous tamoxifen therapy.

For metastatic cancer, Arimidex is often continued long-term until side effects or lack of effectiveness causes a change in medications.

How Well Does Arimidex Work?

In one major clinical trial, over 9,000 postmenopausal women with early stage HR+ breast cancer took Arimidex for 5 years after surgery and initial chemo or radiation.

  • Arimidex lowered the risk of recurrence by 40% compared to no additional treatment.
  • It also reduced the risk of breast cancer developing in the other breast by half.
  • Plus, the risk of dying from breast cancer fell by around 30%.

Several other large trials have also shown:

  • Arimidex is more effective than tamoxifen at preventing HR+ cancer from returning after surgery, if taken for 5 years.
  • It may work well following 2-3 years of tamoxifen treatment.
  • 82% of women saw their tumors stop growing or shrink when taking Arimidex as the first medication for advanced HR+ breast cancer.

While side effects are common when taking Arimidex, for most women the benefits outweigh the risks for approved uses of this treatment.

How Arimidex Differs From Other Hormonal Therapies

The other main hormonal medications used for treating HR+ breast cancer are:

  • Tamoxifen – a selective estrogen receptor modulator (SERM). It blocks estrogen receptors on breast cancer cells. Often used to treat premenopausal women or early stage cancer.
  • Letrozole – an aromatase inhibitor like Arimidex that works similarly by suppressing estrogen production. Main difference is it’s used as the preferred first-line treatment for advanced cancer in postmenopausal women.

Unlike tamoxifen, Arimidex does not actually bind to estrogen receptors on cancer cells. Instead, it drastically lowers overall estrogen levels circulating in the body.

Doctors consider letrozole and Arimidex quite similar medications. Often the choice comes down to insurance coverage or side effect profile on an individual basis.

What To Expect: Dosage, Administration and Duration

  • Arimidex comes as a small oval 1 mg tablet, usually a light blue color.
  • The usual dose is one 1 mg tablet taken orally once per day.
  • It can be taken anytime during the day, with or without food.
  • Swallow the pill whole with water – do not chew, split or crush it.
  • For early stage breast cancer, treatment generally lasts for 5 years after surgery. If cancer returns, treatment may continue long-term.
  • For advanced metastatic cancer, Arimidex is often taken continuously until it stops working or side effects require changing medications.
  • It’s crucial to take this medication every day as prescribed by your doctor. Remember to refill it on schedule so you don’t run out! Taking it regularly maximizes effectiveness.
  • Never share Arimidex tablets with another person. Doses are tailored to the individual.

What If You Miss A Dose?

Don’t panic or double up if you miss one day occasionally due to a busy schedule. Follow these tips:

  • If you remember within 12 hours since your usual time, go ahead and take that day’s tablet.
  • If it has been over 12 hours, just skip the missed dose.
  • Then take your next scheduled pill at the usual time, as normal.
  • Call your doctor if vomiting or diarrhea causes you to miss more than one dose in a row.

Common Side Effects: What To Watch For

While effective for many, adjusting to an aromatase inhibitor like Arimidex can take some time. Some women tolerate it very well with minimal side effects, while others experience more difficulties.

In clinical studies, very common side effects occurring in over 10% of women were:

✔️ Hot flashes and sweating
✔️ Joint pain, stiffness, or swelling ✔️ Muscle pain
✔️ Tiredness and weakness
✔️ Increased cholesterol
✔️ Loss of bone mass (osteoporosis)

These tend to appear within the first couple months and be worst in the first year for most women. They vary widely in severity – while uncomfortable for some, others find them manageable. They often decrease in later years.

Strategies like exercise, calcium, vitamin D, maintaining healthy cholesterol levels or medications can help minimize bone and joint side effects. Vaginal moisturizers, lubricants or low dose vaginal estrogen creams can ease resulting genital dryness or pain with intercourse that occasionally occurs.

Some women may also have:

  • Mild nausea, vomiting, diarrhea or constipation
  • Trouble sleeping
  • Mood changes like irritability or depression
  • Vaginal itching, bleeding or discharge
  • Headaches or dizziness
  • Bone fractures with minor trauma

Contact your doctor promptly if any symptoms:

☢️ Worsen and impact quality of life significantly
☢️ Don’t improve over 6 to 12 months ☢️ Indicate possible allergic reaction – swelling, chest tightness, trouble breathing

Rare but serious risks exist like blood clots, liver damage, severe skin reactions and eye issues. Immediately call your doctor or go to the ER at signs of:

❗Vision changes
❗Abdominal pain, yellow skin/eyes
❗Chest pain, leg swelling, sudden shortness of breath

Other medications or dose adjustments can often help manage difficult side effects. Don’t simply stop Arimidex without medical supervision – an alternative is needed to control cancer growth.

Tips For Taking Arimidex Successfully

  • Keep all medical appointments for bloodwork, exams, bone density tests and imaging scans as recommended by your care team. This allows closely monitoring how well Arimidex is working and catching any problems early.
  • Tell your doctor about any other medications, vitamins or supplements you take. Some can interact with Arimidex by altering estrogen levels. These include certain pain medications, antidepressants, blood thinners, heart medications and others. Always check first before starting something new.
  • Similarly, inform your doctor if starting or stopping herbs like ginseng, ginkgo, lavender, dong quai, evening primrose oil, or the supplement DHEA.
  • Stay active and modify your diet if needed to minimize bone loss, control cholesterol increases or maintain a healthy weight. Ask your doctor for specific advice. Weight-bearing exercise and calcium/vitamin D supplementation helps bones stay strong.
  • Don’t become pregnant while taking Arimidex – it may harm a developing baby. Use reliable non-hormonal birth control if premenopausal or perimenopausal.
  • Tell all of your healthcare providers you are taking Arimidex so they consider potential interactions or effects while planning procedures, surgeries or caring for any other medical conditions you have.

Some women need to switch from Arimidex to a different hormonal therapy over time due to side effects or if breast cancer progresses despite treatment. But remember – over three-quarters of women take Arimidex for years without needing to change course.

While its vital to report concerning symptoms, staying optimistic and focusing on the goal of defeating breast cancer long-term with your medical team sets the stage for success. You’ve got this!

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