Conclusions : International differences in prescriber behaviour may influence , and in turn be influenced by , the conduct of clinical trials .
Objective : International differences are thought to exist in dosages used by clinicians treating mood disorders .
This study examined international dosage differences in antidepressant clinical trials , using a data base formed and maintained as a component of a Cochrane review of comparative clinical trials of fluoxetine .
A randomized, open-label comparison of venlafaxine and fluoxetine in depressed outpatients.
In this r and omized , open-label , 8-week comparative study , the efficacy and safety of venlafaxine and fluoxetine were assessed in out patients with major depression . One hundred forty-five patients were assigned to receive venlafaxine 37.5 mg twice daily or fluoxetine 20 mg once daily . On day 15 , if clinical ly indicated to improve patient response , the dosage could be increased at the investigator 's discretion to venlafaxine 75 mg twice daily or fluoxetine 40 mg once daily . One hundred forty-five patients were evaluated for safety and 110 , for  efficacy  . The mean age was 37 years , and 70 % of the patients were female . In both treatment groups , mean scores on the Hamilton Depression Rating Scale decreased significantly between baseline ( 27.8 , venlafaxine ; 29.2 , fluoxetine ) and the end of the study ( 8.7 , venlafaxine ; 8.2 , fluoxetine ) . Similarly , mean scores on the Montgomery-Asberg Depression Rating Scale decreased significantly between baseline ( 31.4 , venlafaxine ; 31.6 , fluoxetine ) and the end of the study ( 8.3 , venlafaxine ; 7.6 , fluoxetine ) . In venlafaxine patients , the most common adverse events were nausea ( 44.3 % ) , headache ( 40.0 % ) , insomnia ( 31.4 % ) , dizziness ( 30.0 % ) , and dry mouth ( 22.9 % ) ; in fluoxetine patients , they were headache ( 32.0 % ) , nausea ( 28.0 % ) , insomnia ( 24.0 % ) , anxiety ( 21.3 % ) , sleepiness ( 20.0 % ) , and generalized tremor ( 20.0 % ) . The results of this study indicate that venlafaxine is effective and well tolerated for the treatment of major depression at doses of 37.5 or 75 mg twice daily and not significantly different from fluoxetine 20 or 40 mg once daily
Conclusions : International differences in prescriber behaviour may influence , and in turn be influenced by , the conduct of clinical trials .
Objective : International differences are thought to exist in dosages used by clinicians treating mood disorders .
This study examined international dosage differences in antidepressant clinical trials , using a data base formed and maintained as a component of a Cochrane review of comparative clinical trials of fluoxetine .