Nitrazepam - EEG and Sleep

EEG and Sleep

In sleep laboratory studies, nitrazepam decreased sleep onset latency. In psychogeriatric in-patients nitrazepam was found to be no more effective than placebo tablets in increasing total time spent asleep, was found to significantly impair trial subjects abilities to move and carry out everyday activities the next day and it was concluded that nitrazepam should not be used as a sleep aid in psychogeriatric in-patients.

Stage 2 NREM sleep is significantly increased by nitrazepam but SWS stage sleep is significantly decreased by nitrazepam. There is delay in the onset, and decrease in the duration of REM sleep. Following discontinuation of the drug, REM sleep rebound has been reported in some studies. Nitrazepam is reported to significantly affect stages of sleep; a decrease stage 1, 3, and 4 sleep and to increase stage 2. In young volunteers the pharmacological properties of nitrazepam was found to produce sedation, impaired psychomotor performance and standing steadiness. EEG tests showed a decrease of alpha activity and increased the beta activity. These effects increased according to blood plasma levels of nitrazepam. Performance was significantly impaired 13 hours after dosing with nitrazepam as was decision-making skills. EEG tests show more drowsiness and light sleep 18 hours after nitrazepam intake more so than amylobarbitone. Fast activity was recorded via EEG 18 hours after nitrazepam dosing. An animal study demonstrated that nitrazepam induces a drowsy pattern of spontaneous EEG including high-voltage slow waves and spindle bursts increase in the cortex and amygdala, while the hippocampal theta rhythm is desynchronized. Also low-voltage fast waves occur particularly in the cortical EEG. The EEG arousal response to auditory stimulation and to electric stimulation of the mesencephalic reticular formation, posterior hypothalamus and centromedian thalamus is significantly suppressed. The photic driving response elicited by a flash light in the visual cortex is also suppressed by nitrazepam. Estazolam was found to be more potent however. Nitrazepam increases the slow wave light sleep (SWLS) in a dose-dependent manner whilst suppressing deep sleep stages. Less time is spent in stages 3 and 4 which are the deep sleep stages, when benzodiazepines such as nitrazepam are used. Benzodiazepines are therefore not good hypnotics in the treatment of insomnia. The suppression of deep sleep stages by benzodiazepines may be especially problematic to the elderly as they naturally spend less time in the deep sleep stage.