Rats segregated according to low (LA) or high (HA) anxiety levels have been used as an important tool in the study of fear and anxiety. Since the efficacy of an anxiolytic compound is a function of the animal's basal anxiety level, it is possible that chronic treatment with a benzodiazepine (Bzp) affects LA and HA animals differently. Based on these assumptions, this study aimed to provide some additional information on the influence of acute, chronic (18 days) and withdrawal effects (48 h) from diazepam (10 mg/kg), in rats with LA or HA levels, on startle response amplitude. For this purpose, the elevated plus-maze (EPM) test was used. In addition, the role of glutamate receptors of the central nucleus of the inferior colliculus (cIC), the most important mesencephalic tectum integrative structure of the auditory pathways and a brain region that is linked to the processing of auditory information of aversive nature, was also evaluated. Our results showed that, contrary to the results obtained in LA rats, long-term treatment with diazepam promoted anxiolytic and aversive effects in HA animals that were tested under chronic effects or withdrawal from this drug, respectively. In addition, since Bzp withdrawal may function as an unconditioned stressor, the negative affective states observed in HA rats could be a by-product of GABA-glutamate imbalance in brain systems that modulate unconditioned fear and anxiety behaviors, since the blockade of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) and N-methyl-D-aspartate (NMDA) glutamate receptors in the cIC clearly reduced the aversion promoted by diazepam withdrawal.

BACKGROUND. Extreme hormonal and metabolic responses to stress are associated with increased morbidity and mortality in sick adults. We hypothesized that administering deep opioid anesthesia to critically ill neonates undergoing cardiac surgery would blunt their responses to stress and might improve clinical outcomes. METHODS. In a randomized trial, 30 neonates were assigned to receive deep intraoperative anesthesia with high doses of sufentanil and postoperative infusions of opiates for 24 hours; 15 neonates were assigned to receive lighter anesthesia with halothane and morphine followed postoperatively by intermittent morphine and diazepam. Hormonal and metabolic responses to surgery were evaluated by assay of arterial blood samples obtained before, during, and after the operations. RESULTS. The neonates who received deep anesthesia (with sufentanil) had significantly reduced responses of beta-endorphin, norepinephrine, epinephrine, glucagon, aldosterone, cortisol, and other steroid hormones; their insulin responses and ratios of insulin to glucagon were greater during the operation. The neonates who received lighter anesthesia (with halothane plus morphine) had more severe hyperglycemia and lactic acidemia during surgery and higher lactate and acetoacetate concentrations postoperatively (P less than 0.025). The group that received deep anesthesia had a decreased incidence of sepsis (P = 0.03), metabolic acidosis (P less than 0.01), and disseminated intravascular coagulation (P = 0.03) and fewer postoperative deaths (none of 30 given sufentanil vs. 4 of 15 given halothane plus morphine,(P less than 0.01). CONCLUSIONS. In neonates undergoing cardiac surgery, the physiologic responses to stress are attenuated by deep anesthesia and postoperative analgesia with high doses of opioids. Deep anesthesia continued postoperatively may reduce the vulnerability of these neonates to complications and may reduce mortality.

Neuronal circuits across several systems display remarkable plasticity to sensory input during postnatal development. Experience-dependent refinements are often restricted to well-defined critical periods in early life, but how these are established remains mostly unknown. A representative example is the loss of responsiveness in neocortex to an eye deprived of vision. Here we show that the potential for plasticity is retained throughout life until an inhibitory threshold is attained. In mice of all ages lacking an isoform of GABA (gamma-aminobutyric acid) synthetic enzyme (GAD65), as well as in immature wild-type animals before the onset of their natural critical period, benzodiazepines selectively reduced a prolonged discharge phenotype to unmask plasticity. Enhancing GABA-mediated transmission early in life rendered mutant animals insensitive to monocular deprivation as adults, similar to normal wild-type mice. Short-term presynaptic dynamics reflected a synaptic reorganization in GAD65 knockout mice after chronic diazepam treatment. A threshold level of inhibition within the visual cortex may thus trigger, once in life, an experience-dependent critical period for circuit consolidation, which may otherwise lie dormant.

We compared the effect of abrupt discontinuation of therapeutic doses of short half-life and long half-life benzodiazepines in 57 benzodiazepine-dependent patients (daily use, greater than 1 year). Despite the use of a mean daily dose of 14.1 mg of diazepam equivalents, there were notable residual symptoms of anxiety and depression present at intake (Hamilton Rating Scale for Anxiety score, 17.0; Hamilton Rating Scale for Depression score, 14.0). Benzodiazepine intake was stabilized for 3 weeks before double-blind assignment to placebo (n = 47), or continued benzodiazepine use (n = 10). Clinical assessments were performed daily, including benzodiazepine plasma levels. Depending on the outcome criteria used, anywhere from 58% to 100% of patients were judged to have experienced a withdrawal reaction, with a peak severity at 2 days for short half-life and 4 to 7 days for long half-life benzodiazepines. Relapse onto benzodiazepines occurred in 27% of patients who were receiving long half-life benzodiazepines and in 57% of patients who were receiving short half-life benzodiazepines. Baseline predictors of relapse were nonpanic diagnoses, a higher benzodiazepine dose, and a higher Eysenck neuroticism score. A short half-life and higher daily doses were associated with greater withdrawal severity, as were personality traits, such as dependency and neuroticism, less education and higher baseline levels of anxious and depressive symptoms. Patients who were able to remain free of benzodiazepines for at least 5 weeks obtained lower levels of anxiety than before benzodiazepine discontinuation. These results provide a detailed picture of the symptoms, time course, and multidimensional determinants of the benzodiazepine withdrawal syndrome.

In 30 physically and mentally healthy volunteers, 7-chloro-1,3-dihydro-3-hydroxy-1-methyl-5-2H-1,4-benzodiazepin-2-one (temazepam, K 3917) was tested for its sleep inducing action, the subjective quality of sleep and any post-medication effects. Temazepam was orally administered at doses of 15, 20 or 30 mg in hard gelatin capsules or 20 mg in soft gelatin capsules. Nitrazepam (5 mg) and amylobarbitone sodium (100 mg) were used for comparison as well as a placebo. Temazepam showed very much the same effects as they are known from conventional 1,4-benzodiazepines except for its lack of impairment in early morning behavior following night time medication.

Sequelae of early versus late extubation of the trachea in patients following coronary-artery bypass grafting were compared prospectively in 38 patients randomly assigned to one of the two groups. The times to extubation were 2 +/- 2 and 18 +/- 3 hours after operation for the two groups. Comparisons were made between groups for the following five variables: time spent in the intensive care unit; drug utilization in the intensive care unit; cardiopulmonary morbidity; hemodynamic performance; patient stress (plasma norepinephrine levels). The anesthetic technique consisted of induction with thiopental, nitrous oxide, and halothane, followed by maintenance with nitrous oxide and halothane. Pancuronium was the only muscle relaxant administered. Patients whose tracheas were extubated early had muscle relaxants reversed prior to the application of extubation criteria. There was no significant difference between the groups in times spent in the intensive care unit, hemodynamic performances, or plasma norepinephrine levels; however, the patients whose tracheas were extubated early received less morphine and diazepam and suffered significantly less cardiopulmonary morbidity.

In a residential hospital research ward setting the effects of and preference for placebo and various oral doses of pentobarbital and diazepam were studied in volunteer human subjects with documented histories of sedative abuse. Drug-free days alternated with drug administration days throughout the study. After experimenter-scheduled exposures to the test drugs, subjects were given repeated opportunities to choose between two available drug alternatives. In experiment 1, pentobarbital (200-900 mg) produced dose-related increases in subject- and observer-rated drug effects, and subjects generally chose higher pentobarbital doses over lower doses. In experiment 2, diazepam (50-400 mg) produced only modest elevations in drug effect ratings and subjects did not consistently choose higher doses over lower doses. In experiment 3, 400 mg of pentobarbital and 200 mg of diazepam produced subject and observer drug effect ratings of similar magnitude while placebo produced negligible effects. All subjects chose pentobarbital over placebo and diazepam over placebo on all occasions; all subjects chose pentobarbital over diazepam on the majority of choice trials. Clinical impression confirmed by a post hoc analysis of nursing notes indicated that diazepam produced relatively subtle yet reliable changes in the global mood and behavior of the subjects in the direction of increased complaining, dysphoria and disruptivenes. The finding that pentobarbital is preferred to diazepam is compatible with previous human and animal drug self-administration studies as well as clinical information about the abuse of these drugs.

BACKGROUND: Convulsive status epilepticus is the most common neurological medical emergency and has high morbidity and mortality. Early treatment before admission to hospital is best with an effective medication that can be administered safely. We aimed to find out whether there are differences in efficacy and adverse events between buccal administration of liquid midazolam and rectal administration of liquid diazepam in the acute treatment of seizures. METHODS: At a residential school with on-site medical facilities 42 young people with severe epilepsy were enrolled. Continuous seizures of more than 5 min duration were randomly treated with buccal midazolam or rectal diazepam. If the seizure did not stop within 10 min additional medication chosen by the attending physician was administered. We monitored oxygen saturation and blood pressure for 30 min after treatment. The main outcome measures were efficacy, time from arrival of the nurse to drug administration, time from drug administration to end of seizure, and incidence of adverse cardiorespiratory events. FINDINGS: Buccal midazolam was used to treat 40 seizures in 14 students, and rectal diazepam 39 seizures in 14 students. Midazolam stopped 30 (75%) of 40 seizures and diazepam 23 (59%) of 39 (p=0.16). The median time from arrival of the nurse to administration of medication was 2 min. Time from administration to end of seizure did not differ significantly between the two treatments. No clinically important adverse cardiorespiratory events were identified in the two groups. Buccal midazolam was universally acceptable to the nursing and care staff. INTERPRETATION: Buccal midazolam is at least as effective as rectal diazepam in the acute treatment of seizures. Administration via the mouth is more socially acceptable and convenient and may become the preferred treatment for long seizures that occur outside hospital.