Evaluation of the abuse liability of modafinil and other drugs for excessive daytime sleepiness associated with narcolepsy.

Psychostimulants have been used routinely for the treatment of the disabling daytime sleepiness associated with narcolepsy. However, the perceived and real potential for abuse of amphetamine and amphetaminelike stimulants prompted a search for new wake-promoting compounds with lower dependency and abuse liabilities. Modafinil is a novel wake-promoting agent with a mechanism of action that differs markedly from that of amphetamine and amphetamine-like stimulants. In controlled clinical trials, modafinil has been shown to be an effective and well-tolerated treatment for excessive daytime sleepiness (EDS) in patients with narcolepsy. With a benzhydrylsulfinylacetamide structure, modafinil has a low level of solubility in water (< 1 mg/mL) and is unstable at temperatures > or = 180 degrees C, physicochemical properties that reduce the potential for its abuse via intravenous injection and smoking, respectively. Available preclinical and clinical data on the abuse liability of modafinil suggest a much lower potential for abuse and dependency than amphetaminelike stimulants commonly used for treating EDS in patients with narcolepsy. Therefore, modafinil represents a valuable therapeutic option for the treatment of EDS associated with narcolepsy.