Navegando por Palavras-chave "lorazepam"

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    A 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.
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    Effects of lorazepam on deductive reasoning
    (Springer, 2007-11-01) Pompeia, S.; Manzano, G. M.; Pradella-Hallinan, M.; Bueno, O. F. A.; Universidade Federal de São Paulo (UNIFESP)
    Rationale Benzodiazepines slow reasoning performance, but it is still unknown which phase of reasoning is affected and whether this effect is present for different types of relations between entities in reasoning problems.Objectives We investigated which phases of deductive reasoning are affected by lorazepam and whether this effect varies according to the type of relations in deductive reasoning problems.Methods This was a double-blind, crossover design study of acute oral doses of lorazepam (2 mg) and placebo, using young healthy volunteers. We focused on response delay of three separable phases of deductive reasoning and matched working memory tasks (that involved only maintenance of information) the premise processing phase, the premise integration phase, and the validation phase, in which reasoners decide whether a conclusion logically follows from the premises (reasoning task) or is identical to one of the premises (maintenance task). Type of relations in the premises was also manipulated. We employed material that was difficult to envisage visually and visuospatially (subiconic) and material easy to envisage visually or visuospatially.Results Lorazepam slowed response as memory load increased, irrespective of type of relations. It also specifically slowed validation in reasoning problems with visual relations, an effect that disappeared after subtraction of maintenance scores, and increased validation time in problems with subiconic relations, which remained after this subtraction.Conclusion Acute lorazepam administration affected reasoning in two ways: it slowed processing nonspecifically when working memory demands increased and augmented validation time depending on the difficulty in generating and/or manipulating mental representations by the central executive.
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    Effects of lorazepam on visual perceptual abilities
    (Wiley-Blackwell, 2008-04-01) Pompeia, S. [UNIFESP]; Pradella-Hallinan, M. [UNIFESP]; Manzano, G. M. [UNIFESP]; Bueno, O. F. A. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Objective To evaluate the effects of an acute dose of the benzodiazepine (BZ) lorazepam in young healthy volunteers on five distinguishable visual perception abilities determined by previous factor-analytic studies.Methods This was a double-blind, cross-over design study of acute oral doses of lorazepam (2 mg) and placebo in young healthy volunteers. We focused on a set of paper-and-pencil tests of visual perceptual abilities that load on five correlated but distinguishable factors (Spatial Visualization, Spatial Relations, Perceptual Speed, Closure Speed, and Closure Flexibility). Some other tests (DSST, immediate and delayed recall of prose; measures of subjective mood alterations) were used to control for the classic BZ-induced effects.Results Lorazepam impaired performance in the DSST and delayed recall of prose, increased subjective sedation and impaired tasks of all abilities except Spatial Visualization and Closure Speed. Only impairment in Perceptual Speed (Identical Pictures task) and delayed recall of prose were not explained by sedation.Conclusion Acute administration of lorazepam, in a dose that impaired episodic memory, selectively affected different visual perceptual abilities before and after controlling for sedation. Central executive demands and sedation did not account for results, so impairment in the Identical Pictures task may be attributed to lorazeparn's visual processing alterations. Copyright (c) 2008 John Wiley & Sons, Ltd.
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    Lorazepam 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.
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    Stem-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.