Friday, February 15, 2019

Tamoxifen May Reduce Mania in Patients With Bipolar Disorder But Questions Remain

Tamoxifen, a medication commonly used to treat breast cancer, appears to hold some promise as a treatment for mania, according to a systematic review and meta-analysis appearing in the Journal of Psychopharmacology.

Tamoxifen has been proposed as a treatment for bipolar disorder because it acts on cells in a way similar to lithium and valproate—both of which are effective medications for bipolar disorder. However, the current review found most studies focused on the effect of tamoxifen on mania, not on bipolar disorder, and its effects on depression are unknown.

“Tamoxifen appears to be a promising potential treatment for episodes of mania,” wrote Jorge Palacios, M.D., of King’s College, London, and colleagues. “However, the total number of participants in trials to date remains relatively low … and there has been a lack of study of its effects on depressive mood.”

Palacios and colleagues performed a literature search using the Cochrane Central Register of Controlled Trials and other resources for randomized, controlled trials (RCTs) of tamoxifen for bipolar disorder. They identified five placebo-controlled RCTs of tamoxifen in the treatment of acute mania in adults. There were no randomized trials of the agent for bipolar depression or for relapse prevention.

The five placebo-controlled RCTs included in the meta-analysis ran for a duration of three to six weeks and included a total of 164 participants. Tamoxifen was studied as a monotherapy in two of the studies and as an adjunct to lithium or valproate in the other three.

Tamoxifen was found to be superior to placebo in lowering mania scale scores, with greater improvements when used as a monotherapy. Response rates (defined as at least a 50% reduction in the mania rating scale score from baseline to end of treatment) were also higher for patients randomized to tamoxifen, and the overall acceptability (measured by overall drop-out rates) was similar to placebo.

“Tamoxifen has been recommended as an option for pharmacological treatment of acute mania in some, but not all recent guidelines,” the authors wrote. “There remain important unanswered questions to clarify its appropriate use. Future studies could investigate the effects of tamoxifen as an adjunct to dopamine antagonist medications for improved antimanic efficacy and establish its longer-term effects on mood, particularly depression, and relapse.”

For more information, see the Psychiatric News article “Researchers Sum Up Current Knowledge of Bipolar Disorder, Call for More Study.”



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