Residual effects of hypnotics

Ten normal subjects were tested on a large battery of physiological and psychological tests 12 h after a hypnotic dose of butobarbitone sodium (100 or 200 mg) or nitrazepam (5 or 10 mg) and compared with a placebo. The subjects received all five treatments in a balanced design. The tests used included self-ratings, the electroencephalogram, the auditory electroencephalographic evoked response, reaction time, tapping, card-sorting and the digit symbol substitution test. Both drugs were effective hypnotics according to the ratings but butobarbitone had more subjective hangover the following morning. The electroencephalogram showed significant changes after both drugs but the evoked response was affected most by 10 mg nitrazepam. The psychological tests showed some dose-related impairment after both drugs. Bioassay statistics suggested that with respect to these residual effects the relative potency of nitrazepam to butobarbitone was 271.