The aetiology and management of sleep episodes in Parkinson's disease

Levodopa and the dopamine agonists are effective, safe, and well-tolerated drugs for the symptomatic treatment of the dopaminergic-related features of Parkinson's disease (PD). All dopaminergic drugs can cause sedation, gener ally to a similar degree and frequency, and this is an effect that appears dose related. Daytime somnolence is common amongst PD patients and is cause d by numerous factors including disturbed sleep and drug treatment. Eight p atients taking two of the newer dopamine agonists have been described as su ffering from sudden onset of sleep that occurred without warning. However, sleep itself induces an amnestic effect and denial of sedation or somnolenc e prior to onset of sleep is not uncommon. Thus it appears likely that thes e patients fell asleep as an extension of excessive daytime somnolence rath er than experiencing sudden onset of sleep - a phenomenon yet to be observe d in sleep pathology or with drug therapy. The management of excess sedatio n in PD patients should involve a comprehensive appraisal of comorbidity, c omedication, and lifestyle factors before automatically reducing dopaminerg ic therapy.