Navegando por Palavras-chave "flunitrazepam"
Agora exibindo 1 - 4 de 4
Resultados por página
Opções de Ordenação
- ItemSomente MetadadadosA double-dissociation of behavioural and event-related potential effects of two benzodiazepines with similar potencies(Sage Publications Ltd, 2000-09-01) Pompeia, S.; Bueno, OFA; Lucchesi, L. M.; Manzano, G. M.; Galduroz, JCF; Tufik, Sergio [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)This study was designed to explore the role of benzodiazepine affinity to benzodiazepine binding site on acute psychomotor, subjective and memory effects, as well as auditory Event Related Potential (ERP) latencies, in healthy volunteers. Two benzodiazepines with similar affinity to benzodiazepine binding sites, or potency, were compared: the atypical compound lorazepam (2.0 mg), which has been reported to impair priming, and a standard benzodiazepine, flunitrazepam (0.6 mg, 0.8 mg, 1.0 mg). The study followed a placebo-controlled, double-blind, parallel-group design. Sixty subjects completed a test battery before treatment and at theoretical peak plasma concentration of drugs. Lorazepam and 1.0 mg of flunitrazepam led to comparable alterations on psychomotor, subjective and auditory episodic memory measures. A double-dissociation was found for lorazepam and the equipotent dose of flunitrazepam (1.0 mg): lorazepam was more deleterious than flunitrazepam in time taken to identify fragmented shapes. Lorazepam also impaired direct and indirect stem-completion in comparison to placebo, but this effect was abolished when time to identify shapes was used as a covariate. By contrast, 1.0 mg of flunitrazepam prolonged auditory ERP latencies to a greater extent than lorazepam. High affinity to the benzodiazepine binding sites does not seem to explain the consistent lorazepam-induced impairment of indirect stem-completion. Differences in impairment profile between the benzodiazepines employed may relate to the modality (visual or not) of the tasks used.
- ItemSomente MetadadadosFlunitrazepam-induced changes in neurophysiological, behavioural, and subjective measures used to assess sedation(Elsevier B.V., 2003-05-01) Lucchesi, Lígia M. [UNIFESP]; Pompeia, Sabine [UNIFESP]; Manzano, Gilberto M. [UNIFESP]; Kohn, A. F.; Galduroz, José CF [UNIFESP]; Bueno, Orlando FA [UNIFESP]; Tufik, Sergio [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)Introduction: Certain features of event-related potentials (ERPs), electroencephalographic (EEG), and behavioural measures vary with differing states of alertness and/or sedation. Purpose: This study was conducted to investigate changes in several measures usually viewed as reflecting states of sedation/sleepiness associated with the use of a range of doses of the hypnotic benzodiazepine (BZD) flunitrazepam (FNZ). Methods: This was a double blind, independent group design study of the effects of acute oral doses of FNZ in young healthy volunteers. Forty-eight subjects were randomly allocated to one of four groups-FNZ (0.6, 0.8, and 1.0 mg) and placebo (PLAC)-and tested prior to treatment and then in a posttreatment session close to the theoretical peak plasma concentration. ERP latencies and amplitudes were measured at midfrontal (Fz), midcentral (Cz), and midparietal (Pz) using a standard auditory oddball paradigm. EEG changes were assessed at Pz. Behavioural measures included the digit-symbol substitution test (DSST), a cancellation task (CT), and subjective ratings of alertness and attentiveness by the subjects (SUB) and the experimenter (EXP). Results: FNZ led to psychomotor impairments and decreased alertness and attention; these effects were consistent with previous findings. A progressive, dose-related increase in P3 latency occurred in Fz, Cz, and Pz, and there was an increase in N1 (Fz, Cz) and N2 (Fz). N2-P3 amplitude decreased in Fz. EEG power bands beta 1 increased for the two highest doses, but no significant differences were noted in theta, delta, and alpha bands. P3 latencies, experimenter-rated levels of alertness, and DSST scores differentiated all three doses of FNZ from PLAC. Conclusion: the most sensitive measures used were P3 latencies of the ERPs (which varied with FNZ dose), DSST, and the experimenter-rated levels of alertness. However, we found no evidence for the assumption that one single phenomenon was reflected in all measures and different mechanisms were probably involved. Further experiments will be needed for more in-depth probing of the finer mechanisms underlying sedation/sleepiness and how they affect behavioural and eletrophysiological measures of the central nervous system (CNS) function. (C) 2003 Elsevier Science Inc. All rights reserved.
- ItemSomente MetadadadosLorazepam induces an atypical dissociation of visual and auditory event-related potentials(Sage Publications Ltd, 2003-03-01) Pompeia, S.; Manzano, G. M.; Galduroz, JCF; Tufik, S.; Bueno, OFA; Universidade Federal de São Paulo (UNIFESP)Lorazepam has been reported to atypically disrupt visual processing compared to other benzodiazepines (BZs), but it is not known to what extent this effect extends to impairment in other modalities. Our objective was to compare the effects of lorazepam with those of flunitrazepam, a BZ with standard effects, on visual and auditory event-related potentials (ERPs) using the same paradigm. the study followed a placebo-controlled, double-blind, parallel group-design and involved single oral doses of lorazepam (2.0 mg), flunitrazepam (1.2 mg) and placebo. Thirty-six young, healthy subjects completed a test battery before and after treatment including classic behavioural tests, visual and auditory ERPs. Both drugs led to comparable alterations on behavioural tests and double-dissociations were found, indicating that the doses used were equipotent: lorazepam was more deleterious than flunitrazepam and placebo in fragmented shape identification, while simple reaction times were prolonged for flunitrazepam in comparison to lorazepam and placebo. Effects on P3 latencies were also distinct: alterations in both modalities for flunitrazepam were equivalent and greater than placebo's. in contrast, lorazepam at the frontal and central electrode sites led to greater changes in visual than in auditory latency, and also to longer visual latencies than flunitrazepam and placebo, but lorazepam's auditory latency effects were only different to placebo's at the parietal electrode site. Peripheral visual changes were not responsible for these effects. Differences in the impairment profile between equipotent doses of lorazepam and flunitrazepam suggests that lorazepam induces atypical central visual processing changes.
- ItemSomente MetadadadosStem-completion tasks (indirect, direct inclusion and exclusion) are differently affected by equipotent doses of lorazepam and flunitrazepam(Wiley-Blackwell, 2003-10-01) Pompeia, S.; Bueno, OFA; Galduroz, JCF; Tufik, S.; Universidade Federal de São Paulo (UNIFESP)This study was designed to explore the effects on performance in stem-completion tasks of two benzodiazepines (BZ) in equipotent doses: lorazepam, a drug that atypically disrupts perceptual priming, and flunitrazepam, a compound with standard BZ effects. the study followed a placebo-controlled, double-blind, parallel-group design. Thirty-six young and healthy subjects carried out three completion tasks at theoretical peak-plasma concentrations of drugs: (a) indirect tasks, in which the subjects were instructed to complete stems with the first word that came to mind; (b) direct inclusion tasks/cued recall, in which the participants had to try to use words seen at study as completions; and (c) direct exclusion tasks, in which words seen at study were to be avoided. the PDP was applied to the results in the inclusion and exclusion tasks, to obtain indices of explicit/controlled (C) and implicit/automatic (A) memory. the C index was lowered by both BZs and A was equivalent in all treatments, confirming the general amnestic action of BZs. However, lorazepam led to decreases in completions in the indirect and inclusion tasks, while flunitrazepam impaired performance in the exclusion task. the qualitative differences between the drugs in their effects on performance suggest that these BZs may lead to differences in response bias. Copyright (C) 2003 John Wiley Sons, Ltd.