Arimidex Side Effects

Generic Name: Anastrozole

Please note - some side effects for Arimidex may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).

Side Effects of Arimidex - for the consumer

Arimidex

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Arimidex:

Anxiety; back, bone, breast, joint, or pelvic pain; constipation; cough; diarrhea; dizziness; flu-like symptoms (tiredness; muscle aches); headache; hot flashes; loss of appetite; nausea; skin numbness or tingling; sleeplessness; stomach pain or upset; sweating; vaginal dryness; vomiting; weakness; weight gain.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); bone fracture; calf pain, swelling, or tenderness; chest pain; depression; frequent or painful urination; infection (chills; fever; sore throat); mental or mood changes; one-sided weakness; shortness of breath; sudden, severe headache; swelling of the hands or feet; vaginal bleeding or unusual discharge; vision or speech changes.

For the professional

Arimidex

Adjuvant Therapy

Adverse reaction data for adjuvant therapy are based on the adjuvant trial. At a median follow-up of 33 months, the combination of Arimidex and tamoxifen did not demonstrate any efficacy benefit when compared with tamoxifen in all patients as well as in the hormone receptor-positive subpopulation. This treatment arm was discontinued from the trial. The median duration of adjuvant treatment for safety evaluation was 59.8 months and 59.6 months for patients receiving Arimidex 1 mg and tamoxifen 20 mg, respectively.

Adverse events occurring with an incidence of at least 5% in either treatment group during treatment or within 14 days of the end of treatment are presented in Table 8.

Certain adverse events and combinations of adverse events were prospectively specified for analysis, based on the known pharmacologic properties and side effect profiles of the two drugs.

Patients receiving Arimidex had an increase in joint disorders (including arthritis, arthrosis and arthralgia) compared with patients receiving tamoxifen. Patients receiving Arimidex had an increase in the incidence of all fractures (specifically fractures of spine, hip and wrist) [315 (10%)] compared with patients receiving tamoxifen [209 (7%)]. Patients receiving Arimidex had a decrease in hot flashes, vaginal bleeding, vaginal discharge, endometrial cancer, venous thromboembolic events and ischemic cerebrovascular events compared with patients receiving tamoxifen.

Patients receiving Arimidex had an increase in hypercholesterolemia (278 [9%]) compared to patients receiving tamoxifen (108 [3.5%]). Angina pectoris was reported in 71 [2.3%] patients in the Arimidex arm and 51 [1.6%] patients in the tamoxifen arm; myocardial infarction was reported in 37 [1.2%] patients in the Arimidex arm and in 34 [1.1%] patients in the tamoxifen arm.

Results from the ATAC trial bone substudy at 12 and 24 months demonstrated that patients receiving Arimidex had a mean decrease in both lumbar spine and total hip bone mineral density (BMD) compared to baseline. Patients receiving tamoxifen had a mean increase in both lumbar spine and total hip BMD compared to baseline.

First Line Therapy

Arimidex was generally well tolerated in two well-controlled clinical trials (ie, Trials 0030 and 0027). Adverse events occurring with an incidence of at least 5% in either treatment group of trials 0030 and 0027 during or within 2 weeks of the end of treatment are shown in Table 10.

Less frequent adverse experiences reported in patients receiving Arimidex l mg in either Trial 0030 or Trial 0027 were similar to those reported for second-line therapy.

Based on results from second-line therapy and the established safety profile of tamoxifen, the incidences of 9 prespecified adverse event categories potentially causally related to one or both of the therapies because of their pharmacology were statistically analyzed. No significant differences were seen between treatment groups.

Despite the lack of estrogenic activity for Arimidex, there was no increase in myocardial infarction or fracture when compared with tamoxifen.

Second Line Therapy

Arimidex was generally well tolerated in two well-controlled clinical trials (ie, Trials 0004 and 0005), with less than 3.3% of the Arimidex-treated patients and 4.0% of the megestrol acetate-treated patients withdrawing due to an adverse event.

The principal adverse event more common with Arimidex than megestrol acetate was diarrhea. Adverse events reported in greater than 5% of the patients in any of the treatment groups in these two well-controlled clinical trials, regardless of causality, are presented below:

Other less frequent (2% to 5%) adverse experiences reported in patients receiving Arimidex l mg in either Trial 0004 or Trial 0005 are listed below. These adverse experiences are listed by body system and are in order of decreasing frequency within each body system regardless of assessed causality.

Body as a Whole: Flu syndrome; fever; neck pain; malaise; accidental injury; infection

Cardiovascular: Hypertension; thrombophlebitis

Hepatic: Gamma GT increased; SGOT increased; SGPT increased

Hematologic: Anemia; leukopenia

Metabolic and Nutritional: Alkaline phosphatase increased; weight loss

Mean serum total cholesterol levels increased by 0.5 mmol/L among patients receiving Arimidex. Increases in LDL cholesterol have been shown to contribute to these changes.

Musculoskeletal: Myalgia; arthralgia; pathological fracture

Nervous: Somnolence; confusion; insomnia; anxiety; nervousness

Respiratory: Sinusitis; bronchitis; rhinitis

Skin and Appendages:  Hair thinning; pruritus

Urogenital: Urinary tract infection; breast pain

The incidences of the following adverse event groups potentially causally related to one or both of the therapies because of their pharmacology, were statistically analyzed: weight gain, edema, thromboembolic disease, gastrointestinal disturbance, hot flushes, and vaginal dryness. These six groups, and the adverse events captured in the groups, were prospectively defined. The results are shown in the table below.

More patients treated with megestrol acetate reported weight gain as an adverse event compared to patients treated with Arimidex 1 mg (p<0.0001). Other differences were not statistically significant.

An examination of the magnitude of change in weight in all patients was also conducted. Thirty-four percent (87/253) of the patients treated with megestrol acetate experienced weight gain of 5% or more and 11% (27/253) of the patients treated with megestrol acetate experienced weight gain of 10% or more. Among patients treated with Arimidex 1 mg, 13% [33/262] experienced weight gain of 5% or more and 3% [6/262] experienced weight gain of 10% or more. On average, this 5 to 10% weight gain represented between 6 and 12 pounds.

No patients receiving Arimidex or megestrol acetate discontinued treatment due to drug-related weight gain.

Post-Marketing Experience

Hepatobiliary events including increases in alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase have been reported commonly (>1% and <10%) and gamma-GT, bilirubin and hepatitis have been reported uncommonly (> 0.1% and <1%) in patients receiving Arimidex.

Vaginal bleeding has been reported infrequently, mainly in patients during the first few weeks after changing from existing hormonal therapy to treatment with Arimidex. If bleeding persists, further evaluation should be considered.

During clinical trials and postmarketing experience joint pain/stiffness has been reported in association with the use of Arimidex.

Carpal tunnel syndrome was reported more frequently in patients receiving Arimidex than in those receiving tamoxifen in clinical trials; carpal tunnel has also been reported during post-marketing experience with Arimidex. The majority of these reports occurred in patients with identifiable risk factors for the condition.

Arimidex may also be associated with rash including very rare cases of mucocutaneous disorders such as erythema multiforme and Stevens-Johnson syndrome. Very rare cases of allergic reactions including angioedema, urticaria and anaphylaxis have been reported in patients receiving Arimidex.

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