Advanced breast cancer.

Tamoxifen citrate, a nonsteroidal antiestrogen, is a triphenylethylene derivative with both estrogen antagonist (antiestrogen) and agonist (estrogen-like) activity.

Tamoxifen appears to be absorbed slowly following oral administration, with peak serum concentrations generally occurring about 3–6 hours after a single dose.

Hypersensitivity to tamoxifen, patients with leukopenia or thrombocytopenia; pregnancy.

D

It is not known if tamoxifen is distributed into milk. Tamoxifen is rapidly and extensively metabolized. Following oral administration of a 20-mg dose of radiolabeled tamoxifen in women, approximately 65% of the administered dose was excreted in feces over a 2-week period.

Peripheral edema, reduced hemoglobulin, gynecological problems (vaginal bleeding, menstrual irre-gularities).

10-20mg PO BID.