Daytime sleepiness in Parkinson’s disease patient worsened by changing medication between same types of dopamine agonists

A 67-year-old woman with Parkinson’s disease (PD) was being treated with cabergoline. Her excessive daytime sleepiness (EDS) worsened and sleep episodes appeared one week after her medication was changed to pergolide. We speculate that the cause was the change in dopamine agonists that caused a difference in the affinities of the dopamine receptors that affect the sleep-wake mechanism, or an individual difference in sensitivity to dopamine agonists. In treating PD it is necessary to attend to the appearance of sleep episodes or worsening EDS when changing medication from a dopamine agonist to the same type of ergot dopamine agonist.