Modafinil - A review of its pharmacology and clinical efficacy in the management of narcolepsy

Modafinil promotes wakefulness through an as yet unknown mechanism of action. It significantly increases daytime sleep latency and reduces excessive daytime sleepiness (EDS) compared with placebo in patients with narcolepsy. However, the drug does not suppress cataplexy. Although direct comparative dat a are lacking, modafinil offers advantages over amphetamines and methylphenidate in patients with narcolepsy because of its lack of rebound phenomena after treatment withdrawal and its low abuse potential. Clinical trials have shown modafinil to be well tolerated in patients with narcolepsy. Except for headache, which was reported with a significantly greater frequency in modafinil recipients, the tolerability profile of modafinil 200 to 400 mg/day was similar to that of placebo in patients treated for 9 weeks. Preliminary data suggest that the tolerability of modafinil is maintained long term (40 weeks). Thus, modafinil is effective in the treatment of EDS in patients with narcolepsy, although it is not effective against cataplexy. Preliminary findings indicate that, unlike other psychostimulants, the drug is unlikely to be abused and is not associated with withdrawal phenomena. Therefore, modafinil is likely to be an effective therapeutic option for the treatment of EDS in patients with narcolepsy.