An open assessment of the acceptability, efficacy, and tolerance of venlafaxine in usual care settings

Abstract

An open-label study in 518 outpatients with major depression was performed by a collaborative group involving 105 psychiatrists in 22 cities in Mexico. The objectives of this study were to assess the tolerance and efficacy of venlafaxine, a new antidepressive drug, in outpatients in usual care settings. The two largest psychiatric medical associations approved the proposed protocol, and their chairmen coordinated the study. Patients had to comply with the diagnostic criteria for major depression as stated in the Diagnostic and Statistical Manual of Mental Disorders, 3rd edition, revised. The Hamilton Depression rating scale (21 items) and the Clinical Global Impressions (CGI) rating scale were used to assess a patient's clinical response to drug, which was prescribed in different doses (37.5 to 75 mg, 100 to 150 mg, and 175 to 300 mg) according to a patient's status at enrollment. Patients were followed for 6 weeks. A total of 435 patients (84%) completed the study. After 7 days of treatment with venlafaxine, there was a statistically significant improvement in patients with mild-to-moderate depression—those in the 37.5- to 75- mg group (mean CGI improvement, 3.8% to 38.2%) and in the 100- to 150-mg group (mean CGI improvement, 1.3% to 16.7%)—and by day 14 in patients with severe depression—those in the 175- to 300-mg group (mean CGI improvement at day 14, 1.8% to 20.0%). The efficacy of venlafaxine was assessed in all three groups by day 42, with statistically significant improvement observed after treatment with venlafaxine as compared with baseline. The adverse events most frequently associated with the use of venlafaxine were nausea (35.13%) and headache (17.95%), which did not differ in nature and intensity from that reported by other investigators. A total of 83 patients withdrew from the study; 50 of these dropped out due to an adverse event. Although the study design weakened the conclusions drawn from this study, in this 6-week, open-label, uncontrolled trial, venlafaxine appeared to be an efficacious, well-tolerated antidepressant in patients with major depression, with improvement generally detected in about 1 week.