Research Activities, June 2013
Fluoxetine and venlafaxine are effective treatments for depression
Controversy continues to surround the effectiveness of antidepressants, with some suggesting that their benefits are overstated in patients with major depressive disorder. However, two recent studies found that fluoxetine and venlafaxine are effective treatments for depression. Researchers recently reanalyzed the results from 41 randomized controlled trials of fluoxetine and venlafaxine to determine the short-term efficacy of these medications. Their first study found both drugs to be effective for treating major depression in all age groups. Their second study found that both medications decreased suicidal thoughts and behaviors in adult and geriatric patients with no evidence of increased suicide risk in youths. Both studies, supported in part by AHRQ, are summarized here.
Gibbons, R.D., Hur, K., Brown, C.H., and others (2012, June). "Benefits from antidepressants." Archives of General Psychiatry 69(6), pp. 572-579.
The researchers obtained patient data from 12 adult, 4 geriatric, and 4 youth randomized controlled trials of fluoxetine. Data were also analyzed from another 21 adult trials of venlafaxine (11 for the intermediate-release formulation and 10 for the extended-release formulation). All of the information was received from the drugs’ manufacturers and one large National Institute of Mental Health trial. Clinical response rates as well as relapse/remission rates were estimated. Clinical benefits of treatment were found for both drugs. Youths tended to obtain the greatest treatment effect. Only 5.7 percent of children receiving a placebo responded compared to 29.8 percent of children receiving fluoxetine. The difference in remission rate was 30.1 percent. More than half (55.1 percent) of adult patients experienced a 50 percent reduction in the severity of their depression compared to 33.7 percent for patients in the control groups. The remission rate for treated adults was 45.8 percent versus 30.2 percent for controls. Differences in response and remission rates were the weakest for geriatric patients at 9.9 percent and 6.5 percent, respectively. Similar results were also found for venlafaxine, although the intermediate-release formulation had better efficacy than the extended-release formulation.
Gibbons, R.D., Brown, C.H., Hur, K., and others (2012, June). "Suicidal thoughts and behavior with antidepressant treatment." Archives of General Psychiatry 69(6), pp. 580-587.
In their second study, the researchers investigated risk of suicidal thoughts and behaviors in patients taking active medication versus placebo. They analyzed the responses to the suicide items listed in two depression rating scales (one for children and one for adults). They also reviewed adverse event reports of suicide attempts and actual suicides. They found no evidence to suggest an increase in suicide risk from treatment with either fluoxetine or venlafaxine. At baseline, suicide risk was 3 percent for geriatric patients, 5 percent for adults, and 20 percent for youths. Suicidal thoughts and behaviors decreased over time as treatment continued in adults and geriatric patients compared to patients on placebo. A mediational analysis revealed that this was the result of a decrease in depressive symptoms. However, there were no significant drug effects on suicidal thoughts and behavior in children and adolescents.