Sudden sleep attacks with dopamine agonists

• increased daytime sleepiness is a recognised side effect of all dopaminergic drugs
  • a review of 20 publications (2), involving 124 patients with Parkinson's disease, suggested that sudden sleep attacks may occur in people who take any dopamine agonist for Parkinson's disease. The review found that 6.6% (range 0-30%) of such patients have sleep events. The sleep events are different from generalised somnolence and exist as two distinct types:
    • sleep attacks - without warning a patient falls asleep suddenly for a few minutes; there is some controversy about this
    • sleep episodes - in this type a patient sleeps for a period lasting about one hour; there are prodromal signs of tiredness (sometimes as waves of sleepiness) followed by a slow and irresistable dozing off
  • the review suggests that all dopaminergic agents are implicated. Events were also reported after varying durations of exposure to the drug (0-20 years), and with low or high doses
  • the review found that reducing or stopping the drug led to partial or complete cessation of the sudden sleep events. However, symptoms can recur after switching to a different dopamine agonist

Note that the association between dopamine agonists and sleep events has been challenged, with the suggestion that other factors (e.g. Parkinson's disease itself or ageing) might be involved (3).

Reference:

1. MeReC Extra (November 2002), 7.
2. Homann CN et al. Sleep attacks in patients taking dopamine agonists: review. BMJ 2002;324:1483-7.
3. Horne JA.Misperceptions exist about sleep attacks when driving [letter]. BMJ 2002; 325:657.