Management of narcolepsy - Defining the role of modafinil

Narcolepsy is a chronic sleep disorder characterised by excessive daytime s leepiness, with or without cataplexy, sleep paralysis and hypnagogic halluc inations, with an estimated prevalence of 0.02 to 0.05% worldwide. The goal of managing narcolepsy is to keep patients as alert as possible du ring daytime hours and to minimise the incidence of cataplexy. A combinatio n of nonpharmacological (lifestyle and behavioural modifications) and pharm acological treatments may be used to alleviate excessive daytime sleepiness . Stimulants such as amphetamines and methylphenidate have been the mainsta y of pharmacological treatment, although a range of different agents have b een used over several decades. Modafinil, a benzohydrylsulfinyl-acetamide derivative, has demonstrated goo d efficacy in the treatment of excessive daytime sleepiness, but has limite d anticataplectic effects. In clinical studies modafinil 200 to 400 mg/day significantly improved subjective and objective measures of sleepiness and alertness compared with placebo. A long term study of up to 10 years' durat ion showed modafinil to have good to excellent efficacy in 64% of patients. Use of modafinil does not appear to be associated with the development of tolerance or dependence, and it is considered to have limited potential for abuse. Modafinil is generally well tolerated with few adverse effects, the most common being headache, nausea, nervousness and anxiety. It may be coa dministered with drugs for treating cataplexy. The efficacy and the cost ef fectiveness of modafinil in the treatment of narcolepsy have not been compa red with other available agents. Conclusions: Modafinil provides a useful alternative to traditional stimula nts for the treatment of excessive daytime sleepiness associated with narco lepsy. It is well tolerated, may be taken in combination with medications f or cataplexy, and shows long term efficacy without development of tolerance .