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 .
Citalopram treatment of fluoxetine-intolerant depressed patients.
BACKGROUND We assessed the tolerability of and response to  citalopram in depressed patients who had discontinued fluoxetine treatment due to adverse events . METHOD Fifty-five out patients with DSM-IV major depressive disorder and a confirmed history of intolerance to fluoxetine ( mean final dose = 24.6 mg/day ) were switched to citalopram ( 20 mg/day ) after a 2- to 4-week single-blind placebo washout period . During a 6-week , open-label treatment protocol , citalopram could be titrated up to 40 mg/day . Safety and tolerability , including reemergence of symptoms that previously had been associated with fluoxetine , were assessed by recording all spontaneously reported or observed adverse events . Efficacy was evaluated using the Hamilton Rating Scale for Depression ( HAM-D ) , the Clinical Global Impressions ( CGI ) scale , and several other measures . Response was defined as a CGI-Improvement score at endpoint of 1 or 2 ( i.e. , very much or much improved ) . RESULTS Ninety-five percent of patients ( N = 52 ) completed the citalopram trial . The only adverse events reported by more than 5 patients ( > or= 10 % ) were pharyngitis ( 15 % ) and constipation ( 11 % ) , and none of the 3 early terminations were attributed to adverse events . The rate of recurrence of the fluoxetine-associated  adverse events was low , with headache ( 3 [ 27 % ] of 11 cases ) , nausea ( 2 [ 22 % ] of 9 cases ) , and decreased libido ( 5 [ 18 % ] of 28 cases ) being the most common . Significant improvement from baseline HAM-D ( p < .001 ) was observed by the first week of citalopram therapy and continued until study end . The intent-to-treat CGI response rate was 65 % ( 36 of 55 patients ) at study endpoint ; 69 % ( 36 of 52 patients ) of the completers responded . CONCLUSION These data suggest that fluoxetine-intolerant patients can be treated effectively with citalopram
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 .