[Vigilance-decreasing effects of 2 plant-derived sedatives]

Previous studies on the efficacy of valerian extracts have given occasional hints of possible side effects involving impaired vigilance. Because of the currently insufficient knowledge about potential impairment of vigilance by plant-based sedatives, we have conducted a controlled study to assess the effects of two plant-based sleep remedies in comparison with flunitrazepam and placebo after single oral administration. Aim of the study was to derive recommendations concerning potential hazards in driving or operating machinery. Residual sedative effects (hangover) were examined in four groups of 20 healthy volunteers, receiving either tablets containing valerian and hops or syrup containing valerian only or flunitrazepam or placebo; furthermore, immediate sedative effects of the two plant preparations have been examined in comparison with placebo (three groups of twelve healthy volunteers). The tests included objective measurements of cognitive psychomotor performance as well as subjective questionnaires on well-being. Tolerability was assessed from spontaneous reports of side effects and a verbal inquiry at the end of the tests. We found that objectively measurable impairment of performance on the morning after medication occurred only in the flunitrazepam group, a finding which was even more pronounced in the subjective questionnaires. In addition, 50% of the volunteers in the flunitrazepam group reported mild side effects in the inquiry at the end of the tests, compared with only 10% from the other groups. The subjective perception of sleep quality was improved in all three medication groups, when compared to placebo. Examination of acute effects of the plant remedies 1 to 2 hours after administration revealed no changes in the more important lead variables; however, a very slight impairment of vigilance after taking syrup was statistically significant as well as a retardation in the processing of complex information for the tablets. The subjective perception of effects was more pronounced (shaky legs, feeling less active). In conclusion, the residual sedative effects (hangover) observed in some earlier studies cannot be confirmed for the recommended doses of the two plant-based sleep remedies which we have examined with respect to vigilance and cognitive performance. On the contrary: our findings show improved subjective self-assessment (more alert, more active, feeling better). Hangover effects on the following morning need not be a cause for concern, which is of particular interest to car drivers; however, a slight impairment of performance during the first few hours after ingestion should be anticipated. Impairment of vigilance on the morning after ingestion of benzodiazepines, frequently reported and confirmed by our results, constitutes a potential hazard. In this situation, plant remedies such as those examined in this study should be considered as viable alternatives.