What are the similarities and differences between tamoxifen and femara (letrozole)?

Different action: Tamoxifen blocks the estrogen receptor, while Femara (letrozole) blocks the formation of estrogen. Estrogen levels are not lowered by tamoxifen, but they are lowered by femara (letrozole). Both cause hot flashes, bone loss, depression, memory problems and decreased libido. Tamoxifen increases blood clot and uterine cancer risk and causes vaginal discharge, while Femara (letrozole) causes more joint pain and vaginal dryness.

Both are effective: These are two drugs with different mechanisms of action. They are part of breast cancer treatment. Tamoxifen blocks hormone receptors found on some breast cancers. Femara (letrozole) blocks the production of hormones from the adrenal glands, essentially acting as hormone receptors inhibitors. Because of the way these drugs work, Femara (letrozole) can't be used in premenopausal women.