Tamoxifen, a drug approved for treating breast cancer, was found to have benefits in patients with bipolar disorder, decreasing symptoms of the acute mania phase of the disease. Although the study was a small trial, patients with bipolar disorder enrolled in it experienced a decrease in their pathology.
The study was led by Dr. Carlos A. Zarate, MD and was published in the prestigious International Psychiatric journal Bipolar Disorders, a journal dedicated to publishing peer-reviewed works, research, and investigations on this excruciating psychological condition.
Sixteen patients (14 men, 2 women) participated in this clinical trial. Mean age of participants was 35.4, and mean length of illness was 16.4 years. The patients experienced a mean of 33.9 days (current manic episode).
The patients were randomly assigned to receive tamoxifen (20-140 mg/day) or placebo for three weeks. At the end of the study, response rates were 63% for tamoxifen (five of eight patients) and 13% (one of eight) for placebo, the study reported.
Other drugs have been used for have been used for treating bipolar disorders. Lithium, valproate, and carbamazepine are usually prescribed to control acute manic symptoms. However, these drugs have three main drawbacks: they may take more than a week to start working, many patients don’t respond adequately, and many patients can’t stand the side effects of the treatment.
According to the study, patients tolerated well the tamoxifen dosages that were given. The loss of appetite was the main side effect observed. No depression was experienced by the patients in this trial contrary to previously depression experienced in other trial by tamoxifen takers.
Dr. Zarate mentions in the study that his results should be taken with much precaution. He states that the number of patients enrolled is his study is small and that larger controlled trials should be pursued. He also mentions that these results may not apply beyond the treatment of acute symptoms of the bipolar mania.
However, the authors believe that the study raises the possibility of developing faster-acting treatments for the often-destructive early manic phase of the illness. Such new treatments should target a protein named protein kinase C, which is related to symptoms of acute mania. Tamoxifen is a protein kinase C inhibitor.
Another issue with this study arises from the fact that another drug, Lorazepam (Ativan), was used during the trial for four of the tamoxifen patients and six of the placebo patients. Some may think that the observed effects are due to this other drug and not tamoxifen.
Carlos A Zarate Jr, Jaskaran B Singh, Paul J Carlson, Jorge Quiroz, Libby Jolkovsky, David A Luckenbaugh, Husseini K Manji (2007). Efficacy of a protein kinase C inhibitor (tamoxifen) in the treatment of acute mania: a pilot study. Bipolar Disorders 9 (6), 561-570. URL: http://www.blackwell-synergy.com/doi/abs/10.1111/j.1399-5618.2007.00530.x