Anastrozole

Anastrozole is an aromatase inhibitor used alone or with other treatments, such as surgery or radiation, to treat early and advanced hormone receptor-positive breast cancer in postmenopausal women. It can also be used as first-line treatment of advanced breast cancer that has spread or as second-line treatment after tamoxifen therapy.

Anastrozole works by blocking the aromatase enzyme, reducing estrogen production in postmenopausal women. Lower estrogen levels help slow or stop the growth of hormone-dependent breast cancer cells.

It is usually taken as 1 mg tablet once daily. Common side effects include headache, hot flashes, skin rash, loss of appetite, joint pain, and osteoporosis (bone thinning).

• Adjuvant treatment of hormone receptor-positive early breast cancer in postmenopausal women
• First-line treatment of hormone receptor-positive or unknown locally advanced or metastatic breast cancer in postmenopausal women
• Second-line treatment of advanced breast cancer in postmenopausal women with disease progression following tamoxifen therapy

Anastrozole is a non-steroidal aromatase inhibitor. The growth of many breast cancers is stimulated or maintained by estrogens. In postmenopausal women, estrogens are mainly derived from the action of the aromatase enzyme, which converts adrenal androgens (primarily androstenedione and testosterone) to estrone and estradiol. Anastrozole specifically inhibits the aromatase enzyme, suppressing estrogen biosynthesis in peripheral tissues and in cancer tissue itself.

Anastrozole prevents the conversion of androstenedione to estrone and testosterone to estradiol, leading to significantly reduced serum estradiol concentrations.

Anastrozole blocks the aromatase enzyme, inhibiting the conversion of androgens (androstenedione and testosterone) to estrogens (estrone and estradiol). Lower estrogen levels slow or stop the growth of hormone-dependent breast cancer cells.

Adult Dose:

• Recommended dose: 1 mg tablet once daily
• Adjuvant treatment of early breast cancer: Optimal duration unknown
• Advanced breast cancer: Continue until tumor progression

Hepatic Dose: No dose adjustment needed for mild-to-moderate hepatic impairment. Not studied in severe hepatic impairment.

Renal Dose: No dose adjustment necessary for renal impairment.

Special Populations: Pharmacokinetics not affected by age. Safety and efficacy in pediatric patients not established.

Take this medicine in the dose and duration as advised by your doctor. Swallow the tablet whole - do not chew or crush. May be taken with or without food, but take at a fixed time.

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule. Do not double the dose.

Common (>10%):

• Hot flashes
• Asthenia
• Arthritis
• Pain
• Arthralgia
• Hypertension
• Depression
• Nausea and vomiting
• Rash
• Osteoporosis
• Fractures
• Back pain
• Insomnia
• Headache
• Bone pain
• Peripheral edema
• Increased cough
• Dyspnea
• Pharyngitis
• Lymphedema

Rare (<0.01%):

• Skin reactions (lesions, ulcers, blisters)
• Allergic reactions (swelling of face, lips, tongue, throat - difficulty swallowing and/or breathing)
• Liver function changes (jaundice, liver pain or swelling)

Serious Precautions:

• Do not use during pregnancy or in premenopausal women
• Caution in pre-existing ischemic heart disease (increased risk of ischemic cardiovascular events)
• Bone density decrease and osteoporosis may occur - regular bone density testing recommended
• Cholesterol may increase - regular monitoring needed
• May cause weakness and sleepiness - do not drive if affected
• If nausea bothers you, take after meals
• Regular Vitamin D and bone mineral density monitoring recommended

• Pregnancy (Category X) - may cause fetal harm
• Premenopausal women (no clinical benefit)
• Hypersensitivity to Anastrozole or any excipient

• Tamoxifen: Reduces Anastrozole plasma concentration by 27% - do not co-administer
• Estrogen-containing therapies: May diminish Anastrozole's pharmacological action
• Warfarin: Anastrozole does not alter warfarin exposure or anticoagulant activity
• Unlikely to affect other drugs via cytochrome P450 inhibition

[CONSULT YOUR DOCTOR] It is not known whether it is safe to consume alcohol with Anastrozole. Please consult your doctor.

[CONSULT YOUR DOCTOR] Anastrozole is unsafe to use during pregnancy (Category X). There is definite evidence of risk to the developing baby. Discontinue if pregnancy is detected.

[UNSAFE] Anastrozole is unsafe to use during breastfeeding. It is not known whether it is excreted in human milk, and there is potential for serious adverse reactions in nursing infants.

Safety and efficacy in pediatric patients have not been established.

Pharmacokinetics of Anastrozole are not affected by age.

[CAUTION] Use with caution in severe kidney disease. No dose adjustment recommended in mild-to-moderate kidney disease.

[CAUTION] Use with caution in liver disease. No dose adjustment recommended in mild-to-moderate liver disease. Not studied in severe hepatic impairment.

Single doses up to 60 mg in healthy males and 10 mg daily in advanced breast cancer patients were well tolerated. Life-threatening dose not established. No specific antidote; symptomatic treatment required.

Store below 30°C, away from light & moisture. Keep out of reach of children.