The Addition of Amphetamine to Potentially Sedating Medication Regimens: An Exploratory Investigation of the Impact upon Reaction Time and Sustained Attention.

Objectives: The addition of amphetamine to a sedating medication may reduce sedation but does it augment reaction time and sustained attention for workers? The purpose of this exploratory study was gain insight into between group differences that would assist hypothesis formation for a subsequent hypothesis testing study.

Methods: This study examined psychomotor vigilance task (PVT) performance for a group taking potentially sedating medications (opiates, benzodiazepines, anticholinergics, barbiturates or polypharmacy) while taking amphetamine to a group not taking amphetamine. Data was assessed using two-way between groups multivariate analysis of variance.

Results: Multivariate testing found a (p = .05; η2 = .044) difference in combined PVT measures between the amphetamine use groups. Tests of between-subjects effects established ( = .006; η2 = .042) a difference in the number of minor lapses between the groups. Estimated marginal means of minor lapses revealed that the group taking amphetamine had 2.8 times the mean number of minor lapses than the group not taking amphetamine. A non-statistically significant trend was noted for the estimated marginal means of each sedating medication class and the use or nonuse of amphetamines that appears to correspond with the sedating medication's effect upon the cholinergic component of the attention system.

Conclusion: Using PVT data, this exploratory study has provided information useful for generating the hypothesis that co-administration of an amphetamine with a sedating medication will result in arousal with a deficit of sustained attention related to the sedating medication's level of effect upon cholinergic activity.