The comparative efficacy of trazodone and imipramine in the treatment of depression.
OBJECTIVE
To review published clinical trials comparing the efficacy of trazodone with that of tricyclic antidepressant medication.


METHODS
MEDLINE was searched for relevant articles published from 1983 to 1991. The bibliography of a review article was searched for further references.


METHODS
In all, 25 clinical trials were found. Six of these met the methodologic assessment criteria (adapted from the McMaster guidelines for the evaluation of clinical trials), which included the stipulation of a score of 18 or more on the Hamilton depression rating scale and a 50% reduction in that score as an outcome measure.


METHODS
All six studies compared trazodone with imipramine. Data describing response to the treatments were extracted, and post-hoc power estimates were calculated. The analysis also involved statistical tests of a modified null hypothesis, the generation of confidence intervals (CIs) and a meta-analysis.


RESULTS
All the studies found no significant difference in the efficacy of trazodone and imipramine. However, the statistical power of most of them was less than 50% and often less than 10%; thus there was a low probability that differences would be detected. The results of statistical tests of the modified null hypothesis, inspection of the CIs and the results of the meta-analysis all suggested that trazodone, and imipramine are equally efficacious.


CONCLUSIONS
The application of various techniques for the analysis of equivalence data suggests that trazodone and imipramine are of approximately equivalent efficacy. The data are compatible with small differences in efficacy, but the differences are of a magnitude such that they are unlikely to be of clinical significance.
Patten
S B
SB
Alberta Heritage Foundation for Medical Research, University of Calgary.
D002986:Clinical Trials as Topic / Q000592:standards*; D016001:Confidence Intervals; D003866:Depressive Disorder / Q000188:drug therapy*; D006801:Humans; D007099:Imipramine / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D015201:Meta-Analysis as Topic; D012107:Research Design / Q000592:standards; D013810:Therapeutic Equivalency; D014196:Trazodone / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D016896:Treatment Outcome
D007099:Imipramine; D014196:Trazodone