A small, three-week trial of tamoxifen, a drug typically used to treat breast cancer, indicates that it also may decrease symptoms of mania in patients with bipolar disorder, according to a report in the March issue of Archives of General Psychiatry.
Tamoxifen interferes with the effects of the hormone estrogen, which accounts for its effects against breast cancer, according to background information in the article. However, tamoxifen also inhibits the actions of a family of enzymes known as protein kinase C. Abnormal levels of activity by these enzymes have been associated with bipolar disorder and related dysfunctions, such as distractibility, impaired judgments and disorganized thoughts.
Animal studies and human pilot trials have suggested that tamoxifen may be effective in treating mania—an abnormally elevated mood that features impulsive behavior, higher energy and activity levels, and disconnected thoughts—in patients with bipolar disorder. Ayºegül Yildiz, M.D., of the Dokuz Eylül University Medical School, Izmir, Turkey, and colleagues conducted a clinical trial with 66 patients age 18 to 60, all of whom were diagnosed with bipolar disorder and were currently in a manic state or a mixed state that included mania. Participants were randomly assigned to take tamoxifen (40 milligrams to 80 milligrams per day) or identical placebo tablets twice daily for up to three weeks. Participants in both groups also were given up to 5 milligrams per day of the sedative lorazepam as needed to control their symptoms.