Excessive daytime sleepiness (EDS) may limit the symptomatic treatment of
Parkinson's disease and can alter the patient's lifestyle significantly. Ten consecutive patients with
Parkinson's disease on various
dopaminergic drugs and EDS were recruited to a 4-week open-label trial of
modafinil. Patients were evaluated using the Epworth
Sleepiness Scale and Unified Parkinson's Disease Rating Scale part III. All but three patients, with previous history of intolerability of a
dopamine agonist caused by EDS, remained on their baseline medications.
Modafinil was titrated as needed to a maximum of 400 mg/day. The mean Epworth
Sleepiness Scale score at baseline of patients completing the study (n = 9) was 14.22 (+/- 3.03). After completing the study on an average dose of 172 mg/day, the Epworth
Sleepiness Scale score was 6.0 (+/- 4.87). Unified Parkinson's Disease Rating Scale scores were not affected by this medication. Side effects encountered were
headache, generalized paresthesias, and
hallucinations (n = 1 each, the patient developing
hallucinations dropped out of the trial before completing 4 weeks of the study drug). The three patients who did not tolerate any increments of
dopamine agonist before
modafinil were able to tolerate further upward titration of the
dopamine agonist.
Modafinil may be effective in reducing EDS in patients with
Parkinson's disease treated with
dopaminergic drugs. It does not seem to worsen parkinsonian symptoms and may allow further increase in dopaminergic
therapy in patients previously unable to tolerate this because of EDS.