Arterial blood gas tensions during upper gastrointestinal endoscopy.
Arterial blood gas tensions were measured before and during upper gastrointestinal endoscopy, with (group I) and without (group 2) sedation with intravenous diazepam. There was a highly significant fall in the PaO2, which occurred in both groups and was therefore not attributable to diazepam. Measurement of FEV, and FVC before endoscopy had no predictive value for those patients whose PaO2 fell the most. (+info)
The urinary elimination profiles of diazepam and its metabolites, nordiazepam, temazepam, and oxazepam, in the equine after a 10-mg intramuscular dose.
A method for the extraction of diazepam and its metabolites (nordiazepam, temazepam, and oxazepam) from equine urine and serum and their quantitation and confirmation by liquid chromatography-tandem mass spectrometry is presented. Valium, a formulation of diazepam, was administered at a dose of 10 mg intramuscularly to four standard-bred mares. Diazepam is extensively metabolized in the horse to nordiazepam, temazepam, and oxazepam. Diazepam urinary concentrations were found to be less than 6 ng/mL. Nordiazepam was found to be mainly in its glucuronide-conjugated form and was measured out to a collection time of 53-55 h. Oxazepam and temazepam were entirely conjugated, and their urinary concentrations were measured out to collection times of 121 h and 77-79 h, respectively. Diazepam and nordiazepam were measured in equine postadministration serum out to collection times of 6 and 54 h, respectively. Oxazepam and temazepam were not detected in postadministration serum. (+info)
Drug-protein binding and blood-brain barrier permeability.
The permeability surface area (PS) product, an index of permeability of the blood-brain barrier (BBB), was measured by using the in situ perfusion method. In the cerebral circulation, the fraction of drug that permeates into the brain through the BBB is not only the unbound fraction but also the fraction dissociated from the protein in the perfusate. The sum of these two fractions, the apparent exchangeable fraction, was estimated by fitting the parameters of the BBB permeability under the condition of varying BSA concentrations in the perfusate. The unbound fraction of drugs in a buffer containing 0.5 mM BSA was measured by using the ultrafiltration method in vitro, and the apparent exchangeable fraction was measured in vivo by using the intracarotid artery injection method. The apparent exchange fraction was 100% for S-8510, 96.5% for diazepam, 90.9% for caffeine, 38.3% for S-312-d, 33.1% for propranolol, and 6.68% for (+)-S-145 Na, and each of these was higher than the corresponding unbound fraction in vitro in all drugs. The apparent exchangeable fractions, for example, were 8 times higher for diazepam and 38 times for S-312-d than the unbound fractions in vitro. The apparent exchangeable fraction of drugs was also estimated from the parameters obtained with the perfusion method. Because drugs can be infused for an arbitrary length of time in the perfusion method, substances with low permeability can be measured. The apparent exchangeable fractions obtained with this method were almost the same as those obtained with the intracarotid artery injection method. (+info)
Effect of psychotropic drugs on caudate spindle in cats.
To ascertain whether neuroleptics act on the caudate nucleus itself, the effects of these compounds as well as other centrally acting drugs were examined in relation to caudate spindle and EEG arousal responses (sciatic nerve stimulation) in gallamine-immobilized cats. Haloperidol and chlorpromazine enhanced the caudate spindle at a dose which had no effect on the EEG arousal response. On the other hand, clozapine and a higher dose of chlorpromazine enhanced the caudate spindle, but depressed the arousal response. High frequency stimulation of the sciatic nerve suppressed the caudate spindle. Pentobarbital, biperiden and diazepam, while depressing the arousal response, caused an enhancement of the caudate spindle. Imipramine at a low dose had no effect on either response, whereas at a high dose this drug enhanced the caudate spindle with concomitant depression of the arousal response. From these results, it may be concluded that the enhancing action on the caudate spindle induced by haloperidol and a low dose of chlorpromazine is due to an increase in susceptibility of the caudate nucleus itself. In addition, it is suggested that depression of the activating system is involved in an appearance of the caudate spindle. (+info)
Benzodiazepine premedication: can it improve outcome in patients undergoing breast biopsy procedures?
BACKGROUND: Women awaiting needle-guided breast biopsy procedures may experience high anxiety levels. A randomized, double-blind, placebo-controlled study was designed to evaluate the ability of midazolam and diazepam (in a lipid emulsion [Dizac]) to improve patient comfort during needle localization and breast biopsy procedures. METHODS: Ninety women received two consecutive doses of a study medication, one before the mammographic needle localization and a second before entering the operating room. Patients were assigned randomly to receive saline, 2.0 ml intravenously, at the two time points; midazolam, 1.0 mg intravenously and 2.0 mg intravenously; or diazepam emulsion, 2.0 mg intravenously and 5.0 mg intravenously, respectively. Patients assessed their anxiety levels before the needle localization, before entering the operating room, and on arrival in the operating room. Patients completed a questionnaire evaluating their perioperative experience at the time of discharge. RESULTS: Patient satisfaction during needle localization was significantly improved in both benzodiazepine treatment groups (vs. saline). The incidence of moderate-to-severe discomfort during needle localization was lower in the midazolam (20%) and diazepam emulsion (6%) groups compared with the saline group (70%) (P<0.05). The preoperative visual analogue scale anxiety scores were similar in all three groups. In the operating room, however, anxiety scores were 55% and 68% lower after midazolam (21+/-19) and diazepam emulsion (15+/-14) compared with saline (46+/-28). Finally, there was no difference in the time to achieve home-readiness or actual discharge time among the three groups. CONCLUSIONS: Premedication with midazolam or diazepam emulsion improved patients' comfort during needle localization procedures and significantly reduced intraoperative anxiety levels before breast biopsy procedures without prolonging discharge times. Use of diazepam emulsion may be an effective alternative to midazolam in this population. (+info)
Intravenous administration of diazepam in patients with chronic liver disease.
The EEG response and drug kinetics after intravenous infusion of diazepam at 1-0 mg/min until nystagmus, dysarthria, and moderate sedation developed, has been investigated in five normal subjects and 17 patients with chronic liver disease. Diazepam induced adequate premedication with a similar clinical response in all subjects with no adverse reactions. Maximal response was during or within five minutes of infusion. The dose of diazepam required in liver chronic disease was 17-9 +/- 1-4 mg (M +/- SEM) compared with 27 +/- 5-4 mg in controls (p less than 0-01). Dose correlated significantly with serum albumin (p less than 0-05). Baseline mean dominant frequency (MDF) and slow wave index (SWI) significantly correlated with albumin (p less than 0-01). After diazepam, the MDF decreased and SWI increased. The change was greatest at the time of maximal clinical response. It was greater in liverdisease and was greatest in patients with previous hepaticencephalopathy. In spite of reduced dose requirements in liver disease, there was no significant difference in plasma concentration at the end of drug infusion... (+info)
CA1 pyramidal cells were voltage clamped, and GABA was applied to individual cells with a modified U-tube, rapid drug application system. With Vh = -50 mV, inward currents elicited by 10 microM GABA were inhibited by GABAA receptor (GABAR) antagonists and were baclofen insensitive, suggesting that GABA actions on isolated CA1 pyramidal cells were GABAR mediated. GABA concentration-response curves averaged from all cells were fitted best with a two-site equation, indicating the presence of at least two GABA binding sites, a higher-affinity site (EC50-1 = 11.0 microM) and a lower-affinity site (EC50-2 = 334.2 microM), on two or more populations of cells. The effects of GABAR allosteric modulators on peak concentration-dependent GABAR currents were complex and included monophasic (loreclezole) or multiphasic (diazepam) enhancement, mixed enhancement/inhibition (DMCM, zolpidem) or multiphasic inhibition (zinc). Monophasic (70% of cells) or biphasic (30% of cells) enhancement of GABAR currents by diazepam suggested three different sites on GABARs (EC50-1 =1.8 nM; EC50-2 = 75.8 nM; EC50-3 = 275.9 nM) revealing GABAR heterogeneity. The imidazopyridine zolpidem enhanced GABAR currents in 70% of cells with an EC50 = 222.5 nM, suggesting a predominance of moderate affinity alpha2 (or alpha3-) subtype-containing BZ Type IIA receptors. A small fraction of cells (10%) had a high affinity for zolpidem, something that is suggestive of alpha1 subtype-containing BZ Type I receptors. The remaining 30% of cells were insensitive to or inhibited by zolpidem, suggesting the presence of alpha5 subtype-containing BZ Type IIB receptors. Whether BZ Type I and Type II receptors coexist could not be determined. The beta-carboline methyl 6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM) inhibited GABAR currents in all cells at midnanomolar concentrations, but in addition, potentiated GABAR currents in some cells at low nanomolar concentrations, characterizing two groups of cells, the latter likely due to functional assembly of alpha5betaxgamma2GABARs. In all cells, GABAR currents were moderately sensitive (EC50 = 9 microM) to loreclezole, consistent with a relatively greater beta3 subtype, than beta1 subtype, subunit mRNA expression. Two populations of cells were identified based on their sensitivities to zinc(IC50 = 28 and 182 microM), suggesting the presence of at least two GABAR isoforms including alpha5beta3gamma2 GABARs. Consistent with the heterogeneity of expression of GABAR subunit mRNA and protein in the hippocampus and based on their differential responses to GABA and to allosteric modulators, distinct populations of CA1 pyramidal cells likely express multiple, functional GABAR isoforms. (+info)
Benzodiazepine receptor agonists modulate thymocyte apoptosis through reduction of the mitochondrial transmembrane potential.
Peripheral-type benzodiazepines have been shown to exert immunological effects. In this study, we examined the effects of the peripheral-type benzodiazepines on murine thymocytes. Murine thymocytes that were incubated with the peripheral-type benzodiazepines underwent apoptosis associated with the collapse of mitochondrial transmembrane potential (delta psi(m)). The drugs stimulated dexamethasone- and etoposide-induced apoptosis with the enhanced collapse of delta psi(m). The central-type benzodiazepines had no effect on either the delta psi(m) or apoptosis. The reduction of delta psi(m) depended on protein synthesis and protein phosphorylation. These results suggest that the immunomodulating effect of benzodiazepines is in part due to the modulation of thymocyte apoptosis associated with the collapse of delta psi(m). (+info)