In a multicenter, randomized, double-blind study the authors compared the efficacy of
modafinil 400 mg once daily, 400 mg given in a split dose, or 200 mg once daily for maintaining wakefulness throughout the day in patients (N = 32) with
narcolepsy reporting a positive daytime response to
modafinil but late-afternoon/evening
sleepiness. Efficacy evaluations included an extended Maintenance of Wakefulness Test (9:00 am to 9:00 pm), the Clinical Global Impression of Change scale, and the Epworth
Sleepiness Scale.
Modafinil demonstrated significant improvement in wakefulness as assessed by the Epworth
Sleepiness Scale compared with placebo at baseline (all P < 0.001).
Modafinil significantly improved patients' ability to sustain wakefulness, as demonstrated by mean sleep latency at week 3 compared with placebo at baseline (all P < 0.001). The 400-mg split-dose regimen improved wakefulness significantly in the evening compared with the 200-mg and 400-mg once-daily regimen (both P < 0.05). The percentage of patients rated as "much improved" or "very much improved" with respect to evening
sleepiness was 27%, 82%, and 80% in the 200-mg, 400-mg once-daily, and 400-mg split-dose groups, respectively. Adverse events were mild to moderate in nature and included
headache,
nausea, nervousness,
dyspepsia,
pain, and
vomiting (all 6%). Some patients may benefit from 400-mg doses of
modafinil taken once daily compared with 200-mg doses. A split-dose 400-mg regimen may be superior to once-daily dosing for sustaining wakefulness throughout the entire waking day.