Results from several clinical studies designed to assess the effectiveness and tolerability of Reboxetine (Edronax), a new antidepressant agent, were announced recently at the annual meeting of the American Psychiatric Association.
Reboxetine, produced by Pharmacia & Upjohn, is the first of a new class of antidepressant medications known as selective norepinephrine reuptake inhibitors. It works through a novel mechanism of action, affecting the norepinephrine system of the body. Researchers have long suspected that the neurotransmitter norepinephrine plays a major role in depression. In fact, reduced levels of this brain chemical have been linked to several specific symptoms that characterize this disorder, including diminished energy, interest, and motivation.
More specifically, reboxetine works by selectively inhibiting the reuptake process, whereby norepinephrine is drawn back up into the brain. By impairing reuptake, there is an increased supply of norepinephrine available for use. Transmission is concomitantly enhanced in various brain areas.
The results from two eight-week clinical trials of 549 patients with major depression in Europe, Latin America, and Australia demonstrated greater reductions in depression scores (as measured by the Hamilton Depression Scale) with reboxetine versus placebo. When compared to fluoxetine (Prozac®), reboxetine showed larger reductions in depressive symptoms, despite a similar rate of adverse events. Additionally, reboxetine treatment enabled more patients to achieve a normal score on a scale measuring social functioning by the end of the two studies. Social functioning encompasses active social behavior in both personal and occupational settings, as well as self-perception.
Although generally well tolerated in both studies, the most commonly reported side effects of reboxetine are dry mouth, insomnia, constipation, increased sweating, hypotension, urinary hesitancy/retention, paresthesia, tachycardia, and impotence.
Study author Juan Massana, M.D., concludes that these studies provide valuable information on the role of norepinephrine in depression and a possible new treatment option for patients suffering from this disease.