During sleep, some people stop breathing for short periods because of blockage of air passages in the upper respiratory tract. This condition, called obstructive sleep apnea, prevents restful sleep. People with sleep apnea sometimes feel bad, have difficulty thinking clearly, or report daytime sleepiness. The usual treatment involves wearing a special mask during sleep. The mask is part of a device that uses air pressure to keep the air passages open (continuous positive airway pressure, or CPAP). People who either find CPAP uncomfortable or do not feel immediate benefit from it often discontinue therapy. Doctors who treat sleep apnea need approaches that help these people tolerate and continue CPAP. One idea is short-term use of a mild sedative that helps promote sleep when people are first trying CPAP.