Depressed patients who take two medications fare no better than those who only taken one, according to researchers at the University of Texas Southwestern Medical Center.
“Clinicians should not rush to prescribe combinations of antidepressant medications as first-line treatment for patients with major depressive disorder,” said lead study investigator Dr. Madhukar H. Trivedi, professor of psychiatry and chief of the division of mood disorders at UT Southwestern.
“The clinical implications are very clear – the extra cost and burden of two medications is not worthwhile as a first treatment step,” he said.
In the nationwide study, called Combining Medication to Enhance Depression Outcomes (CO-MED), researchers at 15 sites across the country observed 665 patients ages 18 to 75 with major depressive disorder. Three groups were formed according to treatment type and each was prescribed antidepressants already approved by the Food and Drug Administration.
The first group took escitalopram (a selective serotonin reuptake inhibitor, or SSRI, brand name Lexapro) and a placebo; the second group received the same SSRI along with bupropion (a non-tricyclic antidepressant, brand name Wellbutrin); and the third group took two different antidepressants: venlafaxine (a tetracyclic antidepressant, Effexor) and mirtazapine (a serotonin norepinephrine reuptake inhibitor, Remeron).
After 12 weeks of treatment, all three groups showed similar remission and response rates: 39 percent, 39 percent and 38 percent, respectively, for remission; response rates were approximately 52 percent in all three groups. After seven months, remission and response rates remained similar in all three groups, but side effects were more frequent in the third group.
Notably, only about 33 percent of patients with depression enter remission in the first 12 weeks of treatment with the use of antidepressant medication, as Trivedi and colleagues previously reported from the Sequenced Treatment Alternatives to Relieve Depression, or STAR*D, study.
In the realm of depression research, STAR*D was the largest study ever performed concerning the treatment of major depressive disorder and is considered a benchmark. The six-year, $33 million study initially included more than 4,000 patients from sites across the country.
Trivedi said the next step is to study biological markers of depression to see if scientists can predict a patient’s response to an antidepressant medication and therefore enhance the overall outcome.
The study was conducted from March 2008 through February 2009 and will be published in an upcoming issue of the American Journal of Psychiatry.