Anastrozole (Arimidex)

Class of Drugs: Antineoplastic/Non-steroidal aromatase inhibitor

Manufacturer: AstraZeneca

Information on Patient Assistance program:
The Partnership for Prescription Assistance -1-888-4PPA-NOW (1-888-477-2669) or

Cancer Support Network
1-866-99-AZCSN (1-866-992-9276)

Description: Anastrozole is an off-white powder that is administered in tablet form

Ingredient: Anastrozole. There is lactose in the Arimidex tablet - if milk products usually give you diarrhea (lactose intolerance), the lactose in the tablet may causing this effect. Take Lactaid® just before your anastrozole dose.

Use: Anastrozole is used to reduce the amount of circulating estrogen produced by the action of aromatase in post-menopausal women.

Warnings: This drug can cause harm to the fetus if taken while pregnant.

Side Effects: You may experience some side effects such as flu like symptoms, nausea, vomiting or diarrhea, skin rash, hot flashes, vaginal dryness and discomfort, swelling of your hands, feet or lower legs, sinusitis, bronchitis, rhinitis, dizziness, moodiness or depression, anemia, an abnormal decrease of white blood cells and general aches and pains. Contact your health care provider if any of these side effects are severe or cause you discomfort

In early breast cancer the most common side effects include hot flashes, joint symptoms, weakness, mood changes, pain, sore throat, nausea and vomiting, depression, high blood pressure, osteoporosis, swelling of arms/legs and headache. Fractures (including fractures of the spine, hip, and wrist) occurred more frequently with arimidex than with tamoxifen (10% vs 7%).

Most women have little or no nausea, but if nausea is a problem take your anastrozole after eating.

Hot flashes (sudden sweating and feelings of warmth) may occur when you first start taking anastrozole. It will usually subside as you adjust to the medication. If hot flashes are a problem take your anastrozole at bedtime. If night sweats disturb your sleep, try taking your medicine in the morning.

If fatigue (tiredness and lack of energy) is a problem do not drive a car or operate machinery if you are feeling tired. Avoid alcohol which may make you feel more drowsy.

If diarrhea is a problem after trying Lactaid®, avoid high fiber foods such as bran, whole grain breads and cereals, nuts, raw fruits and raw vegetables.

Vaginal dryness may be worsened by anastrozole. If it is a problem try using a water-based vaginal lubricant.

Mild to severe headaches may occur. These can be treated with mild analgesics. Check with your doctor to make sure that any over the counter medication will not interact with other medications that you are taking.

This drug does not cause you to lose your hair, but if hair thinning occurs use a gentle baby shampoo and soft brush. Avoid hair spray, dyes, perms or any other chemicals that may damage your hair.

In advanced breast cancer the most common side effects include hot flashes, nausea, decreased energy and weakness, pain, back pain, bone pain, and increased cough. Joint pain/stiffness has been reported in association with the use of this drug.

Arimidex should not be taken with tamoxifen or estrogen-containing therapies.

References: Anastrozole (Arimidex)

Return to Drug Index

This information is intended as reference and not as medical advice. All treatment decisions should be made with your team of medical professionals and prescriptions must be given by your doctor. See TERMS AND CONDITIONS.