Residual effects of hypnotics: triazolam, flurazepam, and nitrazepam

The residual effects of three hypnotics were investigated by the method of 24-h polygraphy (EEG, EMG, and EOG). The drugs were triazolam 0.25 mg and 0.5 mg, flurazepam 15 mg and 30 mg, nitrazepam 5 mg and 10 mg, and placebo. The subjects were healthy volunteers, eight men and eight women with an average age of 34.3 years. The number of total polygraphic records was 77. Triazolam 0.25 mg and 0.5 mg, flurazepam 30 mg, and nitrazepam 10 mg showed definited sleep inducing and sleep maintenance effects in night recordings. Flurazepam 15 mg and 30 mg and nitrazepam 5 mg and 10 mg were followed by residual effects in morning, afternoon and evening recording periods on the day after the administrations of the hypnotics. However, no effects were seen on the day after the administration of triazolam 0.25 mg and 0.5 mg except for some slight residual effects in the morning. Thus triazolam 0.25 mg and 0.5 mg produces less residual effect than do flurazepam 15 mg and 30 mg, and nitrazepam 5 mg and 10 mg, and 24-h polygraphy is useful for measuring the residual effects of hypnotics.