There may be a slight advantage for doctors in treating patients with a class of antidepressants called serotonin/norepinephrine reuptake inhibitors (SNRIs) over an older class of antidepressants called selective serotonin reuptake inhibitors (SSRIs), according to a study published in the Feb. 15, 2008 issue of Biological Psychiatry.
SNRIs work by increasing serotonin and norepinephrine, normal substances in the brain that help maintain mental balance. SSRIs increase serotonin only.
"Individuals with depression often have to try more than one type of antidepressant before they find a medication that helps," says study author Charles B. Nemeroff, MD, Reunette W. Harris Professor and chair of the Department of Psychiatry and Behavioral Sciences at Emory University School of Medicine.
"This study was conducted to provide clinicians with information that would show whether medications increasing the availability of serotonin and norepinephrine in the brain might be successful in treating a larger population of patients than the medications that contain only serotonin," says Dr. Nemeroff.
Researchers pooled the results of 34 completed double-blind, randomized controlled trials involving nearly 8,000 patients. They then compared the remission rates of the patients in these clinical trials who were given the SNRI venlafaxine (Effexor) to the remission rates of patients using different types SSRIs.
The results of this meta-analysis indicated an advantage in remission rates for venlafaxine over the SSRIs overall. However, of the individual SSRIs, venlafaxine was superior in effectiveness only to fluoxetine (Prozac).
"There have been few, if any, studies comparing the efficacy of different types of antidepressants," notes Dr. Nemeroff. "The information that this study has provided may help guide clinicians in choosing treatments for their patients."