Lorazepam compared with pentobarbital for nighttime sedation.

Lorazepam (0.5, 1, 2, and 4 mg) was compared with pentobarbital (60 and 180 mg) for its effect on sleep in "hospital insomnia." Subjective-response data were collected by research nurses. Lorazepam was found to be a potent nighttime sedative: 1 to 1.25 mg of lorazepam is equivalent to 100 mg sodium pentobarbital for measures of sleep quality and duration. At this dose level it is less effective than 100 mg of pentobarbital as a sleep inducer. Studies at higher doses (up to 4 mg) indicate that lorazepam has a wide therapeutic index.