BETHESDA, Md., Sept. 12 -- Tamoxifen(Drug information on tamoxifen) significantly decreased symptoms of acute mania beginning as early as five days in patients with bipolar disorder in a small pilot study.
The drug, approved to treat breast cancer, maintained its effect throughout a three-week trial with a response rate of 63% for tamoxifen versus 13% for placebo, Carlos A. Zarate, Jr., M.D., of the National Institute of Mental Health, and colleagues reported online in the Sept. issue of Bipolar Disorders.
Tamoxifen is a relatively selective protein kinase C inhibitor with the advantage that it crosses the blood-brain barrier, the researchers wrote.
They reasoned that because tamoxifen inhibits protein kinase C directly, it would produce anti-manic effects more rapidly than previously achieved with lithium(Drug information on lithium) or valproate(Drug information on valproate) (Depacon).
Those two drugs, they said, exert their primary effect considerably upstream of protein kinase C and ultimately work through an indirect cascade of events.