Caffeine counteracts impairments in task-oriented psychomotor performance induced by chlorpheniramine: a double-blind placebo-controlled crossover study
Journal of Psychopharmacology, 06/22/2012
Kim SW et al. – Chlorpheniramine significantly increases subjective sleepiness and objectively impairs psychomotor performance.Methods
- Sixteen healthy young men participated in this study.
- Using a double–blind placebo–controlled crossover design, each subject was administered one of the following conditions in a random order with a one–week interval: ‘placebo–placebo’, ‘4 mg of chlorpheniramine–placebo’, ‘placebo–200 mg of caffeine’ or ‘4 mg of chlorpheniramine–200 mg of caffeine’.
- Before and after the treatments, psychomotor functions were assessed using a battery of tests.
- Additionally, subjective responses were assessed using a visual analogue scale (VAS).
- Psychomotor performance changed over time in different ways according to the combination of study medications.
- In the ‘chlorpheniramine–placebo’ condition, reaction times of the compensatory tracking task were significantly impaired compared with the other three conditions.
- In addition, the number of omission errors of the continuous performance test were significantly greater compared with the ‘placebo–caffeine’ condition.
- However, the response pattern of the ‘chlorpheniramine–caffeine’ condition was not significantly different from that of the ‘placebo–placebo’ condition.
- Changes of VAS for sleepiness were significantly greater in the ‘chlorpheniramine–placebo’ condition compared with the other three conditions.