Acute Effect of Single Oral Administration of Nefazodone and Trazodone of Psychomotor Performance: A Duble-Blind Cross-Over Comparison in Healthy Volunteers

Kim, Chang Yoon; Choi, Sam Wook; Choi, Hyeong Sik; Kim, You Jin; Han, Oh Su

Abstract

OBJECTIVE
New antidepressant, nefazodone is classified as a serotonin -2 antagonist/reuptake inhibitor like old antidepressant, trazodone. Nefazodone, however, differs from trazodone in that it lacks anti-histaminergic properties and in that it has some norepinephrine reuptake inhibitory properties. These differences may account for the differences between the two drugs in the side effect profiles. This study was conducted to compare the acute effects of nefazodone on the psychomotor performance with those of trazodone.
METHODS
The subjects were 12 healthy male volunteers aged between 20-40 years. A single, oral starting dose of nefazodone or trazodone was administered in a double-blind, randomized latin-square design with a 1-week interval between each drug switch. Psychomotor performances were assessed at 1 hour before and at 2 hours after administration of nefazodone 50 mg, nefazodone 100 mg or trazodone 50 mg. The measures of psychomotor performance included Vienna Determination Unit for complex choice reaction time, Critical Flicker Fusion Test, and Grooved Pegboard Test.
RESULTS
In the Vienna Determination Unit, when 'within drug effect' (pre- vs. post-medication) was analyzed, nefazodone 100 mg decreased complex choice reaction time in both subtest 2 and subtest 3. Nefazodone 50 mg also decreased the reaction time in subtest 3 but not in subtest 2 which was more difficult and demanding task than subtest 3. On the other hand, no significant changes in the reaction time were observed with trazodone 50 mg in either subtest 2 or subtest 3. When 'between drug effect' was analyzed, however, the differences between drugs were not found to reach statistically significant level. No significant 'between drug effect' or 'within drug effect' was observed in Critical Flicker Fusion Test and Grooved Pegboard Test.
CONCLUSION
Although the differences between nefazodone and trazodone did not reach statistically significant level, the results on the complex choice reaction time suggest that al least a single starting dose of nefazodone up to 100 mg does not impair psychomotor performances and it might have a less detrimental effect than trazodone on the psychomotor performance.