Effects of flurazepam and zolpidem on the perception of sleep in normal volunteers

In previous studies we have reported that the benzodiazepine hypnotic triazolam and the nonbenzodiazepine zolpidem increase the likelihood that insomniacs will report having been asleep when awakened by an electronic tone of progressive intensity. It has not been known, however, whether this occurs with normal sleepers. In the present study we have administered placebo, flurazepam 30 mg and zolpidem 10 mg to 15 normal sleepers and awakened them with an electronic tone at five points across the night. In contrast to previous reports with insomniacs, both compounds made only modest improvements in sleep. When all time points were combined, subjects reported having been asleep in 40.3, 42.9 and 47.9% of the trials on placebo, flurazepam and zolpidem, respectively (ns). Subjects were accurate in their estimate of total time asleep, and this accuracy was not influenced by the drugs. Similarly, there were no effects on a variety of questions related to dreaming and other cognitive activity during sleep. These results suggest that the effects of these hypnotics, which have been described previously in insomniacs, are not found in normals. Further studies will be necessary to clarify whether such effects in insomniacs are related to the clinical efficacy of hypnotics.