Drugs and Medications to Treat Breast Cancer

Breast Cancer

Treatment for breast cancer is determined according to the stage of the disease. While surgery is the main option for eliminating the malignant tumors from the affected breast, additional therapies are required for killing the malignant cells, preventing spread of the disease and reducing the risk of relapse. Breast cancer medication comprises of chemotherapy drugs, hormone therapy drugs and drugs that target the breast cancer cells.

Medications for Breast Cancer Treatment


Tamoxifen belongs to the class of drugs known as anti-estrogen or selective estrogen receptor modulator. It works by obstructing the female hormone estrogen from attaching to the estrogen receptors in the breast, thereby arresting growth of the breast cancer cells. Tamoxifen is recommended for treating estrogen sensitive breast cancers.


It is taken once or twice a day daily or as directed by the physician. To prevent breast cancer, tamoxifen is often continued for about five years. This breast cancer drug may cause nausea, hot flashes, fatigue, depression, dizziness, thinning of hair, constipation, stomach cramps and weight loss.

Aromatase Inhibitors

The enzyme needed for synthesis of estrogen is known as aromatase. By obstructing the activities of this enzyme, aromatase inhibitors impair estrogen production. Starved of estrogen supply, the estrogen sensitive breast cancer tumors fail to grow. These drugs are used for treating breast cancer only in postmenopausal women.

Aromatase inhibitors approved for treating breast cancer include anastrozole, exemestane, letrozole, fadrozole, vorozole and formestane. Clinical trials have shown that the aromatase inhibitors are superior to the traditional breast cancer drug tamoxifen in treating localized estrogen sensitive breast cancer in postmenopausal women. However, these drugs tend to increase osteoporosis and arthritis risks. Other side effects of the drug include infertility, kidney, liver and adrenal problems.


Fulvestrant belongs to the class of medications called selective estrogen receptor down-regulator (SERD) or estrogen receptor antagonist. It is used for treating hormone receptor positive breast cancer in postmenopausal women. This drug is injected, once a month, into the buttock muscle.


Fulvestrant is usually used for arresting growth of breast cancer tumors that have not responded to tamoxifen. By degrading the estrogen receptors, it stops estrogen supply to the cancer tumors. Nausea, vomiting, loss of appetite, diarrhea, constipation, headache, sore throat, pain in bones and joints, excess sweating, depression and sleeping difficulty are some of the common side effects of the drug.


Trastuzumab inhibits the activities of human growth factor receptor 2 (HER2) a protein that supports growth and survival of the breast cancer cells. Obstructing HER2 helps to kill the malignant cells. Heart damage, skin rash and headache are common side effects of the drug.


Lapatinib works in the same way as trastuzumab. It is a more powerful drug, and is used for treating advanced metastatic breast cancer that has not responded to trastuzumab. Side effects of this drug include fatigue, nausea, vomiting, skin rash, diarrhea and pain in the hands and legs.

Chemotherapy Drugs

Chemotherapy Drugs

Chemotherapy drugs are injected in the vein or given by mouth to breast cancer patients. Some of the drugs used for breast cancer treatment include anthracyclines, cytoxan, taxanes, navelbine, herceptin and methotrexate.

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