Tamoxifen May Help Treat Bipolar Mania
Study Shows Breast Cancer Drug Treats Manic Phase of Bipolar Disorder
Tamoxifen Targets Protein Kinase C continued...
Patients in both groups were also treated with the antianxiety sedative lorazepam, as needed, to help control their symptoms.
At the end of three weeks of treatment, the tamoxifen-treated patients had significantly lower scores on tests designed to measure the severity of manic symptoms, while the scores of placebo-treated patients increased slightly.
Almost half (48%) of patients taking tamoxifen, compared to 5% of placebo-treated patients, responded to the treatment, meaning that they had reductions of at least half in mania scores.
Tamoxifen-treated patients also needed less lorazepam in the second and third weeks of the study.
The findings are published in the March issue of the Archives of General Psychiatry.
Better Treatments Needed for Manic Phase of Bipolar Disorder
About 6 million adults in the U.S. have bipolar disorder, a condition characterized by dramatic mood shifts from manic 'highs' to depressed 'lows.' Manic episodes can last from at least one week to months, and symptoms can include extreme restlessness, sleeplessness, irritability, and distractibility.
It is during this manic phase that bipolar patients most often engage in the risky, out-of-control, pleasure-seeking behaviors.
Yildiz tells WebMD that better treatments for the manic phase of bipolar disorder are badly needed, because current treatments typically take many weeks to work.
"During this time, people can lose their marriages, their jobs, or all their money," she says. "Finding quicker treatments would be very meaningful."
But while tamoxifen is effective, its estrogen-inhibiting action makes it problematic for the long-term treatment of bipolar patients, Manji says.
He adds that a drug that directly targets PKC activity but doesn't block estrogen receptors could represent a big step forward in the treatment of bipolar disorder and possibly other mental illnesses like posttraumatic stress disorder (PTSD) and even alcoholism.
Researchers are working to find such treatments and to target the exact PKC enzymes associated with mania.
"There are about 12 different subtypes of protein kinase C, and we think that two of those are important for the treatment of mania," he says. "If we come up with a treatment that just targets these two, it is likely to be much more effective with fewer side effects."