The number of previous treatments with antidepressants was negatively correlated with treatment outcome .
After a first SSRI , any switch within or between classes of antidepressants appears legitimate ( second SSRI , novel dual-acting antidepressants , selective norepinephrine or nor-adrenergic/dopaminergic agents , or tricyclic anti-depressant or mianserin ) .
No unequivocal evidence is available to prove an advantage of a between-class switch .
OBJECTIVE Selective serotonin reuptake inhibitors ( SSRIs ) are frequently used as a first antidepressant for major depressive disorder but have response rates of 50 % to 60 % in daily practice .
For patients with insufficient response to SSRIs , switching is often applied .
This article aims to systematic ally review the evidence for switching pharmacotherapy after a first SSRI .
Fluoxetine in tricyclic refractory major depressive disorder.
Data regarding open-label treatment with fluoxetine following failure to respond to tricyclic antidepressants ( TCAs ) or intolerance of TCA side effects , suggest a response rate between 51.4 % and 62.1 % , depending on the definition of TCA refractoriness employed . Double-blind study of this issue would extend these findings . Fluoxetine is well tolerated in patients unable to tolerate TCAs .  Within this population , more than 80 % of patients unable to tolerate TCAs found fluoxetine acceptable . Fluoxetine , as an alternative to polypharmaceutical augmentation , may represent a logical choice as the next step in therapy for a patient who has initially been treated with a TCA and has proven refractory or intolerant
The number of previous treatments with antidepressants was negatively correlated with treatment outcome .
After a first SSRI , any switch within or between classes of antidepressants appears legitimate ( second SSRI , novel dual-acting antidepressants , selective norepinephrine or nor-adrenergic/dopaminergic agents , or tricyclic anti-depressant or mianserin ) .
No unequivocal evidence is available to prove an advantage of a between-class switch .
OBJECTIVE Selective serotonin reuptake inhibitors ( SSRIs ) are frequently used as a first antidepressant for major depressive disorder but have response rates of 50 % to 60 % in daily practice .
For patients with insufficient response to SSRIs , switching is often applied .
This article aims to systematic ally review the evidence for switching pharmacotherapy after a first SSRI .