Modafinil for excessive daytime sleepiness in myotonic dystrophy.

The authors conducted an open-label trial of modafinil for excessive daytime sleepiness in myotonic dystrophy. Eleven patients were evaluated: two were not treated because of obstructive sleep apnea, and nine received 200 to 400 mg modafinil/day for an average of 16.4 weeks. There were no major side effects. Average sleep latency as measured by the Multiple Sleep Latency Test increased from 7.3 to 22.7 minutes ( p = 0.00013), and average Epworth Sleepiness Scale score decreased from 13.25 to 7.75 (p = 0.01028). Modafinil shows evidence of effectiveness for excessive daytime somnolence in myotonic dystrophy and should be investigated further.