Aromatase Inhibitor

Aromatase Inhibitor

Aromatase inhibitors (AIs) are a class of drugs used primarily in the treatment of breast cancer and ovarian cancer in postmenopausal women. AIs work by blocking the enzyme aromatase, which turns the hormone androgen into small amounts of estrogen in the body. This means that less estrogen is available to stimulate the growth of hormone-receptor-positive breast cancer cells.

Mechanism of Action

Aromatase inhibitors work by inhibiting the action of the enzyme aromatase, which converts androgens into estrogens by a process called aromatization. By blocking this conversion, AIs reduce the amount of estrogen in the body, slowing or stopping the growth of cancer cells that require estrogen for growth and division.

Types of Aromatase Inhibitors

There are two types of aromatase inhibitors approved to treat breast cancer:

• Nonsteroidal aromatase inhibitors, such as anastrozole (Arimidex) and letrozole (Femara), which stop the production of estrogen in postmenopausal women.
• Steroidal aromatase inactivators, such as exemestane (Aromasin), which permanently bind to aromatase and stop it from making estrogen.

Side Effects

Like all drugs, aromatase inhibitors can cause side effects. Common side effects include hot flashes, joint pain, weakness, mood changes, pain in the hands and wrists (carpal tunnel syndrome), bone loss, and high cholesterol. More serious side effects can include heart problems and osteoporosis.

See Also

• Breast Cancer
• Ovarian Cancer
• Endocrine therapy
• Hormone therapy