Anti-insomnia drugs are medications that help people who have difficulty falling asleep, staying asleep, awakening early, or who have disturbed sleep patterns resulting in insufficient sleep. Physicians prescribe anti-insomnia drugs for short-term or intermittent treatment of insomnia.

Sleep-related complaints such as insomnia and ensuing daytime drowsiness impair the lives of 20-50% of Americans. Sleep problems have been associated with decreased work productivity and absenteeism, increased healthcare utilization, and short-term memory impairment. Also, an estimated 200,000 automobile accidents each year are caused by excessive drowsiness or falling asleep at the wheel. Thus, insomnia and excessive daytime fatigue may be viewed as significant public health problems.

Although sleep is necessary for survival, exactly how it contributes to maintaining health and well-being is unknown. Individual requirements vary widely, ranging from four to ten 10 hours every 24 hours in healthy individuals. Insomnia may be primary (long-standing, with little or no apparent relationship...