Comparison of Droperidol and Midazolam Versus Haloperidol and Lorazepam for Acute Agitation Management in the Emergency Department

BACKGROUND

Acute agitation accounts for up to 2.6% of visits to the emergency department (ED). To date, a standard of care for the management of acute agitation has not been established. Few studies have evaluated antipsychotic and benzodiazepine combinations.

OBJECTIVE

The purpose of this study was to evaluate effectiveness and safety of combination therapy for acute agitation with intramuscular (IM) droperidol and midazolam (D+M) compared with IM haloperidol and lorazepam (H+L) in patients in the ED.

METHODS

This was a single-center, retrospective medical record review of patients presenting to a large, academic ED with acute agitation from July 2020 through October 2021. The primary outcome was percentage of patients requiring additional agitation medication within 60 minutes of combination administration. Secondary outcomes included average time to repeat dose administration and average number of repeat doses required before ED discharge.

RESULTS

A total of 306 patients were included for analysis: 102 in the D+M group and 204 in the H+L group. Repeat dose within 60 minutes occurred in 7 (6.9%) and 28 (13.8%) patients in the D+M and H+L groups, respectively (P = 0.065). A total of 28.4% of D+M patients and 30.9% of H+L patients required any repeat dose during their ED visit. Time to repeat dose was 12 and 24 minutes in the D+M and H+L, respectively (P = 0.22). The adverse event rate was 2.9% in each group.

CONCLUSION AND RELEVANCE

IM D+M resulted in a lower rate of repeat doses of acute agitation medication compared with IM H+L, though this was not statistically significant. Both therapies were safe, and the adverse event rate was low.

Catatonia as the Presentation of Encephalopathy Associated With Autoimmune Thyroiditis: A Case Report and Literature Review

Encephalopathy can be associated with autoimmune disorders such as autoimmune thyroiditis, and it can present with a wide range of neuropsychiatric manifestations. However, it rarely presents with catatonia. We present the case of a middle-aged female with Hashimoto's thyroiditis presenting with catatonia. A literature review of previous similar cases highlighting significant points is also included. A 48-year-old female presented to the emergency department with catatonic symptoms that had worsened over the previous 5 days. A similar condition was reported to have occurred and resolved spontaneously 3 months earlier. On examination, the patient appeared uncooperative and unresponsive. She showed typical symptoms of catatonia, with a score of 21 points on the Bush-Francis Catatonia Rating Scale. Routine tests were within normal ranges except for an elevated level of C-reactive protein and an elevated erythrocyte sedimentation rate. Computed tomography, magnetic resonance imaging, and cerebrospinal fluid analysis were all normal. An electroencephalogram showed diffuse delta-theta range slowing with no epileptiform discharges. Lorazepam was initiated but did not control the catatonic symptoms. Re-evaluation revealed thyroid swelling and elevated levels of thyroperoxidase antibodies. IV methylprednisolone was therefore initiated and produced complete resolution of the catatonic symptoms in 4 hours. The patient was discharged and prescribed prednisone 1 mg/kg daily. At follow-up, the patient continued to show complete resolution of the catatonic symptoms. It is noteworthy that the patient developed hypothyroidism 6 months after this catatonic episode for which levothyroxine 50 mcg/d was prescribed. Encephalopathy associated with autoimmune thyroiditis can initially present with catatonic symptoms in euthyroid cases. The mainstay of treatment is steroids which result in complete resolution of the catatonic symptoms.

Efficacy and Safety of Anxiolytics in Mohs Micrographic Surgery: A Randomized, Double-Blinded, Placebo-Controlled Trial

BACKGROUND

Patient anxiety can complicate surgical outcomes by elevating blood pressure, increasing the need for postoperative pain management, and reducing overall patient satisfaction. Despite the use of anxiolytic medications in outpatient procedures, there is limited comparative evidence on the efficacy and safety of these agents in Mohs micrographic surgery.

OBJECTIVE

To compare the effectiveness and safety of different preprocedural anxiolytic agents in Mohs surgery on perioperative patient anxiety and patient satisfaction.

MATERIALS AND METHODS

A double-blinded, randomized, placebo-controlled trial was conducted of 6 different preprocedural anxiolytic agents (lorazepam, diazepam, alprazolam, gabapentin, pregabalin, and melatonin) in 350 patients undergoing Mohs surgery. Anxiety and vital signs were recorded.

RESULTS

Diazepam demonstrated a statistically significant, sustained reduction in anxiety levels compared with placebo ( p = .03). Gabapentin significantly reduced early anxiety ( p = .02). Alprazolam showed a trend to early anxiety reduction ( p = .08). Lorazepam ( p = .73), pregabalin ( p = .53), and melatonin ( p = .24) failed to reduce patient anxiety compared with placebo at any time point. No anxiolytic significantly impacted any patient vital sign or cognition.

CONCLUSION

Although short-acting benzodiazepines and gamma-aminobutyric acid medications may have transient anxiolytic effects, a single oral dose of 5 mg of diazepam can provide a sustained anxiolytic effect in Mohs surgery, with excellent patient safety.

Anxiolytics cause anxiety in pancreatic cancer

Benzodiazepines (BZDs) are commonly prescribed for pancreatic cancer patients. To investigate the correlation between BZDs and survival outcomes a recent study by Cornwell et al. found that lorazepam (LOR) correlates with poor survival. The mechanistic study shows that LOR increases interleukin 6 (IL6) expression in cancer-associated fibroblasts via GPR68.

Surge of Midazolam Use in the Midst of Lorazepam Shortage

BACKGROUND

Lorazepam is a widely prescribed benzodiazepine that is used to manage anxiety, insomnia, and status epilepticus and is used for pre-anesthetic care as well as several off-label indications including aggression, alcohol withdrawal, panic disorder, chemotherapy-associated anticipatory nausea, and catatonia. Recent increases in demand, manufacturing changes, and quality control issues have resulted in a shortage of injectable and oral lorazepam, prompting clinicians to use alternatives. One such alternative is midazolam, a drug that has been used primarily in the intensive care unit and anesthesia settings.

PROCEDURES

This article examines the significant pharmacologic differences between lorazepam and midazolam. In addition, this article provides dosage guidelines based on the current scientific knowledge and recommendations for conversion equivalencies.

RESULTS

The clinical preference for lorazepam can be attributed to its simpler metabolism with no active metabolites, better suitability for patients with less severe hepatic and renal impairment, less risk of adverse reactions, fewer drug-drug interactions, and greater desirability for special populations. In periods of shortages, midazolam has been shown to be effective for a number of off-label uses. To manage conditions that have not been extensively studied, clinicians may opt to use conversion equivalencies, with the caveat that guidelines may vary greatly between institutions and online sources; therefore, it would be best to start low and titrate slowly.

CONCLUSIONS

Our goal is to aid clinicians in safely and effectively prescribing midazolam during the shortage of injectable lorazepam so that patients are provided the same effects and benefits.

Mental health and drug use in college students: Should we take action?

BACKGROUND

College students are vulnerable to suffering from anxiety and depression. Moreover, mental disorders can contribute to drug consumption or inappropriate use of prescribed drugs. Studies on this topic in Spanish college students are limited. This work analyses anxiety and depression and psychoactive drug intake pattern in the post-COVID era in college students.

METHODS

An online survey was conducted among college students from UCM (Spain). The survey collected data including demographic, academic student perception, GAD-7 and PHQ-9 scales, and psychoactive substances consumption.

RESULTS

A total of 6798 students were included; 44.1 % (CI95%: 42.9 to 45.3) showed symptoms of severe anxiety and 46.5 % (CI95%: 45.4 to 47.8) symptoms of severe or moderately severe depression. The perception of these symptoms did not change after returning to face-to-face university classes in the post-COVID19 era. Despite the high percentage of cases with clear symptoms of anxiety and depression, most students never had a diagnosis of mental illnesses [anxiety 69.2 % (CI95%: 68.1 to 70.3) and depression 78.1 % (CI95%: 77.1 to 79.1)]. Regarding psychoactive substances, valerian, melatonin, diazepam, and lorazepam were the most consumed. The most worrying issue was the consumption of diazepam, 10.8 % (CI95%: 9.8 to 11.8), and lorazepam, 7.7 % (CI95%: 6.9 to 8.6) without medical prescription. Among illicit drugs, cannabis is the most consumed.

LIMITATIONS

The study was based on an online survey.

CONCLUSIONS

The high prevalence of anxiety and depression aligned with poor medical diagnosis and high intake of psychoactive drugs should not be underestimated. University policies should be implemented to improve the well-being of students.

Lorazepam Stimulates IL6 Production and Is Associated with Poor Survival Outcomes in Pancreatic Cancer

PURPOSE

This research investigates the association between benzodiazepines (BZD) and cancer patient survival outcomes, the pancreatic cancer tumor microenvironment, and cancer-associated fibroblast (CAF) signaling.

EXPERIMENTAL DESIGN

Multivariate Cox regression modeling was used to retrospectively measure associations between Roswell Park cancer patient survival outcomes and BZD prescription records. IHC, H&E, Masson's trichrome, RNAscope, and RNA sequencing were used to evaluate the impact of lorazepam (LOR) on the murine PDAC tumor microenvironment. ELISA and qPCR were used to determine the impact of BZDs on IL6 expression or secretion by human-immortalized pancreatic CAFs. PRESTO-Tango assays, reanalysis of PDAC single-cell sequencing/TCGA data sets, and GPR68 CRISPRi knockdown CAFs were used to determine the impact of BZDs on GPR68 signaling.

RESULTS

LOR is associated with worse progression-free survival (PFS), whereas alprazolam (ALP) is associated with improved PFS, in pancreatic cancer patients receiving chemotherapy. LOR promotes desmoplasia (fibrosis and extracellular matrix protein deposition), inflammatory signaling, and ischemic necrosis. GPR68 is preferentially expressed on human PDAC CAFs, and n-unsubstituted BZDs, such as LOR, significantly increase IL6 expression and secretion in CAFs in a pH and GPR68-dependent manner. Conversely, ALP and other GPR68 n-substituted BZDs decrease IL6 in human CAFs in a pH and GPR68-independent manner. Across many cancer types, LOR is associated with worse survival outcomes relative to ALP and patients not receiving BZDs.

CONCLUSIONS

We demonstrate that LOR stimulates fibrosis and inflammatory signaling, promotes desmoplasia and ischemic necrosis, and is associated with decreased pancreatic cancer patient survival.

Percutaneous absorption and Skin accumulation of Lorazepam-Diphenhydramine- Haloperidol Carbopol gel in Porcine Ear Skin

This study presents the formulation and evaluation of an ABH Carbopol gel containing lorazepam (Ativan®), diphenhydramine hydrochloride (Benadryl®), and haloperidol (Haldol®) for treating chemotherapy-induced nausea and vomiting (CINV) in hospice patients. ABH PLO gel is widely used for this purpose due to its low cost and presumed efficacy. However, previous studies, including one conducted by the authors, have reported insufficient drug absorption from the ABH PLO gel. Here we hypothesized that the ABH Carbopol gel would provide superior percutaneous absorption of the drugs. ABH Carbopol gel was characterized for pH, viscosity, thermal properties, and infrared spectroscopy. The percutaneous absorption and skin retention of the gel was evaluated across porcine ear skin using Franz diffusion cells, and the drug concentrations were determined by high-performance liquid chromatography. The pH of the ABH Carbopol gel was found to be 6.80 ± 0.33, and the retention time of diphenhydramine, haloperidol, and lorazepam were 4.73, 7.11, and 18.69 minutes, respectively. The thermogram of the ABH Carbopol gel indicates the drugs were present in the dissolved state. Based on the flux data, the estimated steady-state concentration (Css) of diphenhydramine, haloperidol, and lorazepam were found to be 44.64 ng/ml, 2.58 ng/ml, and 20.1 ng/ml, respectively. These values were significantly higher than those obtained from the ABH PLO gel. In conclusion, the ABH Carbopol gel provides a promising alternative to the ABH PLO gel for treating CINV in hospice patients. Further studies are required to validate these findings in clinical settings.

Prescribing Practices for Agitation Medication in Obese Patients Admitted to the Emergency Department

INTRODUCTION

Weight is a factor that influences the dosages of many medications, although no clinical studies have evaluated this factor in the use of agitation medications in the obese population. The objectives of this study were to assess the need for weight considerations in dosing antipsychotics and benzodiazepines for patients with agitation and to assess prescribing patterns in agitated patients.

METHODS

This retrospective cohort study compared outcomes between obese and nonobese adult patients who received at least one parenteral administration of an antipsychotic or benzodiazepine for agitation in the emergency department. The primary outcomes were total antipsychotic and benzodiazepine doses within 24 hours (in chlorpromazine equivalents and lorazepam equivalents, respectively). Key secondary outcomes included antipsychotic and benzodiazepine doses used for first administration, incidence of repeat emergency medication administration within 24 hours, time to next administration, and number of repeat administrations within 24 hours.

RESULTS

The study examined 115 patient encounters in each cohort of patients in the study. The baseline characteristics of the 2 study cohorts were similar. Both groups had similar mean 24-hour antipsychotic usage [272.7 chlorpromazine equivalents (nonobese cohort), 313.5 chlorpromazine equivalents (obese cohort); P=0.157] and mean 24-hour benzodiazepine usage [0.9 lorazepam equivalents (both cohorts); P=0.750]. Differences between the study cohorts on all of the secondary outcomes were also not statistically significant (P>0.05).

DISCUSSION

This study did not find the use of higher dosages of agitation medication in the obese compared with the nonobese population. Future prospective trials, with possible emphasis on individual medications, specific etiologies of agitation, or morbid obesity, are required to confirm this finding or to elucidate potential differences in optimal medication dosages for the obese population.

Methamphetamine-associated catatonia: Case series and systematic review of the literature from 1943-2020

BACKGROUND

Catatonia due to a general medical condition may result from a variety of causes, including substance intoxication and withdrawal. Stimulants are occasionally associated with catatonia, though there has been little investigation of methamphetamine's relationship to catatonia. Here we present 5 cases of catatonia associated with methamphetamine use and a systematic review of the associated literature from 1943 to 2020.

METHODS

We performed a systematic review of the literature and present 5 cases of catatonia evaluated using the Bush-Francis Catatonia Rating Scale and KANNER catatonia rating scale.

RESULTS

Methamphetamine use was associated with catatonia in a small number of cases in the literature. However, some of these reports included other possible etiologies. The patients in our case series met DSM-5 criteria for catatonia due to a general medical condition, with all reporting recent methamphetamine use and testing positive for amphetamines on urine drug screen.

CONCLUSIONS

Given the ongoing rise in methamphetamine use in the United States, it is important that clinicians understand that methamphetamine use can be associated with catatonia. Patients with methamphetamine-associated catatonia may respond favorably to lorazepam and require shorter hospital stays than other catatonic patients. Lastly, methamphetamine-associated catatonia highlights how alteration in dopamine function and projections may be a critical neural mechanism underlying catatonia in general.

Analgesia and Sedation at Terminal Extubation: A Secondary Analysis From Death One Hour After Terminal Extubation Study Data

OBJECTIVES

To describe the doses of opioids and benzodiazepines administered around the time of terminal extubation (TE) to children who died within 1 hour of TE and to identify their association with the time to death (TTD).

DESIGN

Secondary analysis of data collected for the Death One Hour After Terminal Extubation study.

SETTING

Nine U.S. hospitals.

PATIENTS

Six hundred eighty patients between 0 and 21 years who died within 1 hour after TE (2010-2021).

MEASUREMENTS AND MAIN RESULTS

Medications included total doses of opioids and benzodiazepines 24 hours before and 1 hour after TE. Correlations between drug doses and TTD in minutes were calculated, and multivariable linear regression performed to determine their association with TTD after adjusting for age, sex, last recorded oxygen saturation/F io2 ratio and Glasgow Coma Scale score, inotrope requirement in the last 24 hours, and use of muscle relaxants within 1 hour of TE. Median age of the study population was 2.1 years (interquartile range [IQR], 0.4-11.0 yr). The median TTD was 15 minutes (IQR, 8-23 min). Forty percent patients (278/680) received either opioids or benzodiazepines within 1 hour after TE, with the largest proportion receiving opioids only (23%, 159/680). Among patients who received medications, the median IV morphine equivalent within 1 hour after TE was 0.75 mg/kg/hr (IQR, 0.3-1.8 mg/kg/hr) ( n = 263), and median lorazepam equivalent was 0.22 mg/kg/hr (IQR, 0.11-0.44 mg/kg/hr) ( n = 118). The median morphine equivalent and lorazepam equivalent rates after TE were 7.5-fold and 22-fold greater than the median pre-extubation rates, respectively. No significant direct correlation was observed between either opioid or benzodiazepine doses before or after TE and TTD. After adjusting for confounding variables, regression analysis also failed to show any association between drug dose and TTD.

CONCLUSIONS

Children after TE are often prescribed opioids and benzodiazepines. For patients dying within 1 hour of TE, TTD is not associated with the dose of medication administered as part of comfort care.

Visual compatibility and particle counter evaluations of syringes of intramuscular psychotropic coadministered solutions

BACKGROUND

Patients in the acute phase of agitation can require the administration of multiple drugs by intramuscular injection in order to temporarily stabilise their condition. Administration of multiple psychotropic medications in a single syringe can be beneficial to both the patient and healthcare professionals. However, there are very little data in the literature regarding psychotropic drug compatibility in syringes for acute agitation.

OBJECTIVE

The aim of this study was to assess the visual compatibility of various combinations of 12 intramuscular psychotropic medications in syringes, and to validate compatibility with the use of a particle counter. The medications evaluated were benztropine mesylate, diazepam, dimenhydrinate, diphenhydramine hydrochloride, haloperidol lactate, hydroxyzine, lorazepam, loxapine, methotrimeprazine, midazolam, olanzapine and zuclopenthixol acetate.

METHODS

Compounded solutions of medication combinations underwent visual inspection initially and after 0.25, 0.5, 1, 2 and 4 hours using a white background and a black background. In order to validate the compatibility results, the presence of particulate matter was determined by light obscuration.

RESULTS

This study identified 35 combinations that were visually compatible and 35 that were visually incompatible. We chose eight highly clinically relevant combinations to test using the requirements of the United States Pharmacopoeia (USP) chapter 788 (Particulate Matter in Injections). Of those eight, six were physically compatible, including the triple combinations of lorazepam and haloperidol with either benztropine or diphenhydramine.

CONCLUSION

These physical compatibility results will give healthcare professionals an idea of the possible compatible combinations of psychotropic drugs in syringes, and thus complete some of the missing data in the literature.

Accumulation and risk prioritization of psychoactive substances in the critically endangered Yangtze finless porpoise

Psychoactive substances have been identified as a kind of emerging contaminants in aquatic environment and pose potential adverse effects on aquatic animals. Yangtze finless porpoise, a critically endangered species in China, is also facing the threat of psychoactive substances. In this study, the accumulation characteristics and risk prioritization of psychoactive substances were investigated in Yangtze finless porpoise collected from Poyang Lake (PYL) and Tian-E-Zhou Oxbow (TZO) in Yangtze River basin. The levels of psychoactive substances were detected in the range of below method detection limits (MDLs) to 98.4 ng/mL in the serum of Yangtze finless porpoise. Codeine (COD) and methamphetamine were identified as the major substances due to the highest residual levels with a median concentration of 0.72 ng/mL and 0.33 ng/mL, respectively. The total concentrations of psychoactive substances in the porpoise collected from TZO was significantly higher than those from PYL. Risk analysis based on effect ratio derived from the ratio of steady-state psychoactive substance serum concentration in the porpoise and human therapeutic plasma concentration revealed that COD was the substance with the highest risk among the psychoactive substances detected, followed by lysergic acid diethylamide (LSD), morphine, alprazolam (ALPZ) and lormetazepam. Location-specific risk prioritization of psychoactive substances found that the top 3 substances are LSD, lorazepam (LORZ) and ALPZ in PYL, and COD, LSD and LORZ in TZO. The results disclose the accumulation of psychoactive substances in Yangtze finless porpoise and suggest that the potential adverse effects should be concerned.

Comparison of constructed wetland performance coupled with aeration and tubesettler for pharmaceutical compound removal from hospital wastewater

Pharmaceutical compounds being able to alter, retard, and enhance metabolism has gained attention in recent time as emerging pollutant. However, hospitals which are part of every urban landscape have yet to gain attention in terms of its hospital wastewater treatment to inhibit pharmaceutical compounds from reaching environment. Hence this study evaluated performance of constructed wetland in combination with tubesettler and aeration based on removal efficiency and ecological risk assessment (HQ). The removal efficiency of constructed wetland with plantation was higher by 31% (paracetamol), 102% (ibuprofen), 46%, (carbamazepine), 57% (lorazepam), 54% (erythromycin), 31% (ciprofloxacin) and 20% (simvastatin) against constructed wetland without plantation. Constructed wetland with aeration efficiency increased for paracetamol, ibuprofen, carbamazepine, lorazepam, erythromycin, ciprofloxacin, and simvastatin removal efficiency were higher by 58%, 130%, 52%, 79%, 107%, 57%, and 29% respectively. In constructed wetland with plantation, removal efficiency was higher by 20% (paracetamol), 13% (ibuprofen), 4% (carbamazepine), 14% (lorazepam), 34% (erythromycin), 19% (ciprofloxacin) and 7% (simvastatin). High ecological risk was observed for algae, invertebrate and fish with hazard quotient values in range of 2.5-484, 10-631 and 1-78 respectively. This study concludes that if space is the limitation at hospitals aeration with constructed wetland can be adopted. If space is available, constructed wetland with tubesettler is suitable, economic and environmentally friendly option. Future research works can focus on evaluating other processes combination with constructed wetland.

Alprazolam and lorazepam overdose and the absence of brainstem reflexes

Benzodiazepines (BZDs) rarely cause respiratory depression and death. On the other hand, high-dose BZDs may lead to profound sedation and diminished brainstem functions that mimic other structural brain lesions as described in our case: a 70-year-old unresponsive woman. She was hypothermic and had rapid shallow breathing. Her Glasgow Coma Scale score was E1V1M4, with pinpoint pupils and absent corneal, oculocephalic and oculovestibular reflexes. Other physical exams, laboratory testing and brain imaging were unremarkable. After two doses of 0.4 mg naloxone and intravenous thrombolytics were given, there were no significant responses, and the diagnosis remained a mystery. The cause of her unconsciousness was uncovered when her husband found empty bags of 80 tablets of alprazolam and lorazepam. Her consciousness and brainstem reflexes improved dramatically after 0.25 mg of intravenous flumazenil. The blood for BZDs concentration showed alprazolam 268 ng/mL (20-40 ng/mL), lorazepam 861 ng/mL (20-250 ng/mL) and their metabolites.

AiRDose: Developing and Validating an Augmented Reality Smartphone Application for Weight Estimation and Dosing in Children

OBJECTIVES

Inaccurate weight estimation is a contributing factor to medical error in pediatric emergencies, especially in the prehospital setting. Current American Heart Association guidelines recommend the use of length-based weight estimation tools such as the Broselow tape. We developed the AiRDose smartphone application that uses augmented reality to provide length-based weight estimates, as well as medication dosing, defibrillation energy, and equipment sizing recommendations; AiRDose was programmed to use Broselow conversions to obtain these estimates. The primary objective was to compare the length estimated by AiRDose with the actual length obtained by the standard tape measure. The secondary objectives were to compare the estimated weights and critical medication doses from AiRDose with current established methods.

METHODS

In this prospective validation study, lengths and estimated weights were obtained for children presenting to 2 emergency departments using AiRDose, Broselow, and a standard tape measure; actual weight was recorded from the patient chart. Using the AiRDose estimated weights, hypothetical doses of epinephrine and lorazepam were calculated and compared with doses recommended via Broselow and to actual weight-based doses. Spearman rank correlation coefficients were calculated. We defined an acceptable difference of 20% between AiRDose and standard measurements as clinically relevant.

RESULTS

Five hundred forty-nine children (mean age, 4.8 years; standard deviation [SD], 2.9 years) were recruited. There were 99.6% of AiRDose lengths within a 20% difference of tape-measure lengths. There was a significant correlation between AiRDose and tape-measure length measurements (r = 0.989, P < 0.0001), and between AiRDose and Broselow weights (r = 0.983, P < 0.0001) and AiRDose and actual weights (r = 0.886, P < 0.0001). AiRDose lorazepam and epinephrine doses correlated significantly with Broselow lorazepam (r = 0.963, P < 0.0001) and epinephrine (r = 0.966, P < 0.0001) doses.

CONCLUSIONS

Anthropometric estimates and medication dose recommendations provided by AiRDose strongly correlate with established techniques. Further study will establish the feasibility of using AiRDose to accurately obtain weight estimates and medication doses for pediatric patients in the prehospital setting.

Simultaneous extraction and analysis of clozapine and lorazepam from human plasma using dual solvent-stir bar microextraction with different acceptor phases followed by high-performance liquid chromatography ultra-violet detection

A new design of dual solvent stir bar microextraction (DSSBME) was developed and combined with HPLC-UV for the simultaneous extraction of clozapine (CLZ) and lorazepam (LRP) from human plasma with different acceptor phases. Two short hollow fibers immobilized with an organic extraction solvent were used as the solvent bars for microextraction of CLZ and LRP from the sample solution. The solvent bars were fixed with a staple pin which served as the stirrer. The target analytes were simultaneously and selectively extracted from the sample solution into their corresponding solvent bar. Extraction parameters such as organic solvent type, pH of the sample solution, the acceptor phase concentration, salt incorporation into the solution, stirring rate, and extraction time were optimized to achieve the best extraction results. Under the optimum conditions (1-undecanol as extraction solvent, pH of sample solution = 9.0, 10% w/v NaCl, concentration of HCl = 10 mM, concentration of NaOH = 100 mM, stirring rate of 1400 rpm and extraction time of 30 min at ambient temperature) the limit of detection for CLZ was 0.4 ng mL^-1 and for LRP it was 1.1 ng mL^-1. The linear range for CLZ was 1.3-1000.0 ng mL^-1 (R² = 0.9991) and for LRP it was 3.6-800.0 ng mL^-1 (R² = 0.9993). Extraction recovery and the enrichment factor for CLZ were 95.4% and 343 and for LRP they were 74.3% and 263, respectively. Finally, the method developed was successfully applied for the simultaneous determination of CLZ and LRP in human plasma samples.

Solid-state characterization and in vitro dissolution behavior of lorazepam: Hydroxypropyl-β-cyclodextrin inclusion complex

The objectives of this research were to prepare and characterize inclusion complexes of lorazepam with hydroxypropyl-β-cyclodextrin and to study the effect of complexation on the dissolution rate of lorazepam, a water-insoluble drug. The phase solubility profile of lorazepam with hydroxypropyl-β-cyclodextrin was an AP-type, indicating the　formation of 2:1 stoichiometric inclusion complexes. Gibbs free energy values were all negative, indicating the spontaneous nature of lorazepam solubilization, and they decreased with an increase in the cyclodextrin concentration, demonstrating that the reaction conditions became more favorable as the concentration of cyclodextrins increased. Complexes of lorazepam were prepared with cyclodextrin using various methods such as physical mixing, kneading, spray-drying, and lyophilization. The complexes were characterized by differential scanning calorimetry, Fourier-transform infrared, scanning electron microscopy, and powder X-ray diffraction studies. These studies indicated that a complex prepared by lyophilization had successful inclusion of the lorazepam molecule into the cyclodextrin cavity. Complexation resulted in a marked improvement in the solubility and wettability of lorazepam. Among all the samples, a complex prepared with hydroxypropyl-β-cyclodextrin by lyophilization had the greatest improvement in the in vitro rate of lorazepam dissolution. The mean dissolution time for lorazepam decreased significantly after preparing complexes and physical mixtures of lorazepam with cyclodextrin. The similarity factor indicated a significant difference between the release profiles of lorazepam from complexes and physical mixtures and from plain lorazepam. Tablets containing complexes prepared with cyclodextrins had significant improvement in the release profile of lorazepam as compared to tablets containing lorazepam without cyclodextrin.

[Antiepileptic drugs in North America]

In this review study, second-generation antiepileptic drugs (AEDs) (levetiracetam, gabapentin, topiramate, lamotrigine, zonisamide, oxcarbazepine, vigabatrin, pregabalin, rufinamide, tiagabine, lacosamide, and felbamate) and injectable AEDs (levetiracetam, lacosamide, fosphenytoin, lorazepam, and valproic acid) available in North America were compared with those available in Japan. Three second-generation AEDs (gabapentin, topiramate, and lamotrigine) were recently approved in Japan. Levetiracetam is currently under review for approval by the Japanese regulatory agency. An ideal AED would have a broad-spectrum activity to control multiple types of seizures, favorable safety profile, limited potential for drug-drug interaction, many bioequivalent formulations, long half life to allow infrequent administration, and antiepileptogenic effects that may provide a fundamental cure of epileptic patients by suppressing the development of epileptogenic network and neutralizing previously established epileptogenic foci in the brain. The second-generation AEDs have been developed to possess some of these ideal properties. All the second-generation AEDs are efficacious for the treatment of patients with partial seizures. In addition, levetiracetam, topiramate, lamotrigine, and zonisamide are effective for the treatment of patients with generalized tonic-clonic seizures, absences, myoclonic seizures, Lennox-Gastaut syndrome, and West syndrome; however, lamotrigine is not effective for the treatment of patients with myoclonic seizures. Rufinamide and felbamate are useful for the treatment of patients with Lennox-Gastaut syndrome; however owing to its serious adverse effects, including aplastic anemia and hepatic failure, felbamate is used as the last resort for the treatment of patients with intractable seizures. Vigabatrin is particularly effective for the treatment of patients with West syndrome; however, the patients need to be regularly monitored for the development of peripheral visual field defect. Gabapentin, oxcarbazepine, vigabatrin, and tiagabine are ineffective for the treatment of patients with absences and/or myoclonic seizures and may aggravate these conditions. Treatment with levetiracetam or topiramate (off-label use) is the new option for patients with refractory status epilepticus, which is characterized by downregulation of the inhibitory gamma-aminobutyric acid system, because these drugs act via different mechanisms and are rapidly titratable, especially intravenous levetiracetam. The pharmacokinetic profiles of levetiracetam, gabapentin, and pregabalin are favorable: these drugs exhibit minimal protein binding, do not undergo hepatic metabolism, are not involved in any clinically relevant drug interactions, and rarely lead to the development of serious adverse effects. In general, levetiracetam is probably the closest to being the ideal AED because of its broad-spectrum favorable pharmacokinetic profile and safety profile as well as because of the availability of its parenteral formulation. Among the injectable AEDs, fosphenytoin is a water-soluble prodrug and is used to treat patients with status epilepticus. Systemic and local side effects of this drug are fewer than those of phenytoin. Lorazepam, a benzodiazepine is used as the first-line AED for the treatment of patients with status epilepticus. The effects of this drug are more prolonged than those of diazepam. Intravenous administration of valproic acid is regarded as a new treatment option for patients with status epilepticus, because sedative and negative effects on the cardiorespiratory system of this drug are lesser than those of the traditional injectable AEDs. These novel medications will aid the improvement of the quality of life of epileptic patients through improved seizure control and reduced adverse effects.

Ability of practitioners to identify solid oral dosage tablets

PURPOSE

Physicians' and pharmacists' ability to correctly identify three commonly used oral dosage forms was assessed.

METHODS

A list of physicians and pharmacists was obtained from two urban teaching hospitals. A total of 100 pharmacists and physicians were randomly selected and their ability to correctly identify three commonly used tablets was tested. Participants were also asked about their experiences and views on current resources and alternatives for identifying oral dosage forms. Tablet-identification exercises were performed by physicians and pharmacists in their usual practice settings. Participants could consult the resources usually available to them for the identification of unknown medications.

RESULTS

A total of 300 observations were made in the tablet-identification exercise (100 participants, three tablets per participant). The tablet was correctly identified in 190 of the observations (63%). The brand-name tablet, the generic tablet, and the nonprescription generic tablet were correctly identified in 78%, 64%, and 48% of the observations, respectively. Only 18 physicians (36%) and 24 pharmacists (48%) correctly identified all three tablets, whereas 10 physicians (20%) and 5 pharmacists (10%) could not correctly identify any of the tablets. The mean time required to identify a tablet was 3.65 minutes. Pharmacists most often used electronic resources (52%), while physicians relied on print resources. Overall, 77% expressed dissatisfaction with the current system and 91% favored a universal imprint coding system for oral dosage forms.

CONCLUSION

Physicians and pharmacists failed to correctly identify three commonly prescribed tablets more than a third of the time. The brand-name tablet was correctly identified more often than were the prescription generic and nonprescription generic products.

Specific effects of an amnesic drug: effect of lorazepam on study time allocation and on judgment of learning

We investigated the effects of lorazepam, a benzodiazepine, on the allocation of study time, memory, and judgment of learning, in a cognitive task where the repetition of word presentation was manipulated. The aim was to assess whether lorazepam would affect the learning processes and/or whether the participants would be aware of the amnesic difficulty. A total of 30 healthy volunteers participated in the study, 15 of whom received a capsule containing the lorazepam drug (0.038 mg/kg) and 15 a placebo capsule. First, the accuracy of delayed judgments of learning (JOL) was measured in both groups. For the JOL ratings, results showed that all the participants benefited from word repetition. Although the overall performance was lower in the lorazepam than in the placebo group, the accuracy of the JOL ratings was preserved by the drug. Second, all the participants benefited from the repetition of learning, although the performances of the lorazepam-treated subjects remained lower than those of the placebo participants. The repetition of learning had an effect on JOL in both groups. Finally, the time spent learning each (allocation study time) pair of words was measured. For the placebo group, results revealed that study time decreased significantly with the frequency of presentation. For the lorazepam group, no effect of presentation frequency was found. Overall, our findings suggest that the lorazepam drug has a differential effect on the monitoring and the control processes involved in a learning task. The implications of these findings are discussed within the theoretical framework of metacognition.

Dynamic competition between contour integration and contour segmentation probed with moving stimuli

Line-ends, corners and junctions are important singularities for form analysis, object recognition, depth ordering or motion processing. In this study, we investigate the extent to which processing the motion of line ends depends on the spatial configuration of their immediate surround. To that aim, we used two vertical collinear line segments, translating clockwise or anti-clockwise along a circular path, together with a direction discrimination task. Direction discrimination was measured independently for outer line-ends--at both segments extremities--and inner line-ends--in between collinear segments--using line segments partially occluded by invisible masks such that the direction of either inner or outer line-ends' motion was restricted to a sinusoidal translation along a horizontal axis, and thus irrelevant for the motion task. Under these conditions, access to the direction of inner line-ends is longer and more difficult than it is for outer line-ends. Subsequent experiments show that these effects depend on the degree of collinearity between line segments. Similar experiments were performed after volunteers took a dose of Lorazepam, a benzodiazepine that facilitates the fixation of GABA on GABAA receptors. The results show that the differences between the processing of inner and outer line-ends is reduced, suggesting that the effect of the surround is modulated by inhibitory mechanisms. Using a simple model, we propose that this effect can be explained by a competition between a segmentation process based on surround suppression and contour integration through long-range horizontal connections, at or prior to motion processing stages.

[Intratracheal intubation without muscle relaxant with the use of remifentanil-propofol]

OBJECTIVES

To assess tracheal intubation conditions after induction of anaesthesia with remifentanil and propofol, using itemized scoring criteria.

STUDY DESIGN

Clinical, prospective, open, non comparative trial.

PATIENTS

One hundred consecutive patients undergoing surgery not requiring muscle relaxation, during the study period extended over 12 months.

METHODS

After premedication with lorazepam (2 mg) the day before and hydroxyzine (100 mg) one hour before surgery, anaesthesia was induced with remifentanil administered continuously with a syringe pump at a rate of 1.20 +/- 0.06 micrograms.kg-1.min-1 and propofol (3 mg.kg-1 IV bolus). The trachea was intubated two minutes later and mouth opening, glottis exposure, glottis opening, movements, additional anaesthetic agents and chest rigidity were recorded.

RESULTS

Intubation conditions were excellent in 87% of patients, and the tube was inserted rapidly, within two minutes. However in 38% of patients the cuff inflation caused cough. In 13%, glottis opening was delayed and intubation required three minutes. A major decrease of arterial pressure and heart rate was recorded in 9 and 6% of patients respectively.

CONCLUSION

Induction of anaesthesia using remifentanil and propofol allows satisfactory tracheal intubation without a muscle relaxant. However this technique is contraindicated: a) in patients with a full stomach, as intubation is not always successful at the first attempt; b) in patients scheduled to undergo neurosurgery or ophthalmic surgery, as tracheal intubation may elicit cough, increasing intra-cranial and intra-ocular pressure; c) in patients in poor circulatory status, as it decreases significantly arterial pressure and heart rate.

A method to produce sedation in critically ill patients

OBJECTIVE

To evaluate a protocol based on continuous infusion of a benzodiazepine and morphine to produce apnea/decreased respiratory effort as an adjunct to complex mechanical ventilation in patients with respiratory failure.

DESIGN

Observational report of consecutive patients.

SETTING

University medical intensive care unit.

PATIENTS

Seventeen consecutive patients with acute respiratory failure requiring high levels of sedation and/or paralysis to facilitate mechanical ventilation were studied.

INTERVENTIONS

Patients were started on a continuous infusion of a benzodiazepine and morphine soon after mechanical ventilation was instituted. The dosages of the benzodiazepine and morphine were increased to the end point of diminished respiratory effort or apnea depending on the clinical status of the patient and ventilatory mode. This regimen was supplemented with single doses of neuromuscular blocking agents (NMBAs) only as the dosages of benzodiazepine/narcotic were being titrated. The benzodiazepine/narcotic agents were then gradually reduced as the patient's condition improved, often using an oral route of administration.

MEASUREMENTS AND RESULTS

The benzodiazepine/morphine combination produced apnea and diminished respiratory effort in patients requiring sedation from 2 to 50 days, including those with hemodynamic instability, hepatic dysfunction, renal dysfunction, and sepsis. The combination allowed the use of NMBAs to be minimized. There was no evidence of worsened hemodynamic instability as a result of the administration of these agents. The gastrointestinal tract could be used for nutrition in 8 of the 17 patients.

CONCLUSIONS

Continuous infusion of a benzodiazepine and morphine controlled the respiratory rate in patients with severe respiratory failure requiring complex mechanical ventilatory support.

Effect of oral clonidine premedication on anesthetic requirement, hormonal response, hemodynamics, and recovery in coronary artery bypass graft surgery patients

STUDY OBJECTIVE

To examine how premedication with clonidine affects opioid use, hemodynamic effects, hormonal responses, and recovery effects.

DESIGN

Double blind, placebo-controlled study.

SETTING

Operating room and surgical intensive care unit of a university medical center.

PATIENTS

54 patients undergoing elective coronary artery bypass graft (CABG) surgery.

INTERVENTIONS

Patients received approximately 5 micrograms/kg of oral clonidine or a placebo together with 40 micrograms/kg lorazepam 90 minutes prior to titrated sufentanil induction of anesthesia. Thirty minutes prior to cardiopulmonary bypass, a second dose of either approximately 5 micrograms/kg clonidine or placebo was given as a slurry via a nasogastric tube.

MEASUREMENTS AND MAIN RESULTS

Opioid use, hemodynamic effects, hormonal responses, and recovery effects were recorded. Values for ten hemodynamic variables were compiled on the evening prior to surgery, prior to induction, and during seven additional events and compared. Catecholamines and beta-endorphins were measured prior to induction, after intubation, and after sternotomy. The amount of sufentanil used for induction, maintenance, and total opioid were compared. The times to awakening and response to verbal commands were compared. The two groups exhibited similar patient demographics, cardiopulmonary bypass time, and duration of surgery. Patients receiving clonidine required significantly (p < 0.04) less sufentanil for induction (clonidine: 2.19 +/- 0.95 micrograms/kg vs. placebo: 2.93 +/- 1.07 micrograms/kg) and total amount of sufentanil (clonidine: 9.1 +/- 3.9 micrograms/kg vs. placebo: 11.7 +/- 4.6 micrograms/kg). Patients receiving clonidine required significantly (p < 0.01) less isoflurane (9.7 +/- 6.8 MAC min vs. 19.7 +/- 9.9 MAC min) to maintain heart rate (HR) and mean arterial pressure (MAP) to within 15% of baseline without significant differences in other vasoactive drugs. Catecholamine concentrations were significantly (p < 0.02) lower in patients receiving clonidine without any difference in beta-endorphin concentrations. Patients receiving clonidine had significantly (p < 0.02) lower HR, systolic arterial pressure, MAP, and systemic vascular resistance prior to induction than patients receiving placebo without differences in other hemodynamic variables.

CONCLUSION

Clonidine decreases opioid use and lowers hormonal response while maintaining stable hemodynamics in patients undergoing CABG with sufentanil anesthesia.

The effect of heavy social drinking on recall and event-related potentials

OBJECTIVE

It has been suggested that alcohol-related brain impairments progress on a continuum from subtle deficits in social drinkers through to end-state Korsakoff syndrome. The aim of the present study was to investigate whether heavy levels of social drinking have an adverse effect on sober cognitive functioning in young nonalcoholic adults.

METHOD

Event-related potentials (ERPs) were recorded from heavy ( > 200 gm/week) and light ( < 20 gm/week) male social drinkers under the effects of a pharmacological challenge (lorazepam-ATIVAN) and a placebo. The heavy (n = 14) and light (n = 14) social drinkers completed a free-recall task with a rare word probability of .30.

RESULTS

Analysis of the P300 component of the ERP to recalled and not-recalled words found that P300 amplitude in heavy social drinkers (HSDs) was reduced following placebo compared to the light social drinkers (LSDs). Lorazepam produced a distinctive pattern of anterograde memory deficits in both groups and reduced P300 amplitude to rare words in the LSDs compared to both the placebo treatment and the HSDs.

CONCLUSIONS

The differences in central nervous system functioning evident between HSDs and LSDs were reflected in ERP deviations in both the presence and absence of lorazepam. Even though no definite statements can be made because of the small sample size, the results appear to indicate that HSDs have an impairment in their information-processing ability in the absence of an acute inhibitory agent (e.g., alcohol or a benzodiazepine) as well as a differential response to the depressant effects of lorazepam.

Encoding, remembering and awareness in lorazepam-induced amnesia

The effects of lorazepam (1,2 mg) and placebo on encoding, remembering and awareness were assessed in a study with 54 healthy volunteers. All subjects studied stimulus materials in a levels of processing (L-o-p) task. Half the subjects were assessed on an explicit memory task of word recognition and the other half were given an implicit memory task of word-stem completion. Following the implicit task, awareness of retrieval was further investigated by questions and by subjects' recollective experience in recognising the actual words they had completed from stems. L-o-p effects and marked lorazepam-induced impairments were found in the implicit task of word-stem completion although the interaction between L-o-p and drug effects emerged only as a trend in the data. Lorazepam-induced impairments on stem-completion may then be explained at least in part as being due to contamination by explicit retrieval processes, but we cannot rule out the possible role of drug effects on perceptual processes at encoding. Results from responses to "awareness" questions and from analysis of subsequent recollective experience indicated that subjects were not aware of using explicit retrieval during the implicit task. Results also replicated previous findings showing that both lorazepam and L-o-p independently affect performance in an explicit memory task of word recognition. Thus drug-induced deficits at encoding persist regardless of the level at which information is initially processed.

Rat brain monoamine oxidase A and B inhibitory (tribulin) activity during drug withdrawal anxiety

Morphine (10 mg/kg), ethanol (8% w/v, 2 ml/kg), nicotine (0.1 mg/kg), cannabis extract (200 mg/kg), lorazepam (10 mg/kg) and ondansetron (0.1 mg/kg) were each administered to rats twice daily i.p. for 14 days and the anxiogenic response following their withdrawal was monitored by the elevated plus-maze test 24 h later. Brains were removed and endogenous monoamine oxidase (MAO) A and B inhibitory activity (tribulin) levels measured on day 14 and 24 h after drug withdrawal in different groups of animals. Morphine, ethanol, lorazepam and nicotine withdrawal was associated with significant anxiety and corresponding increase in brain tribulin activity, particularly its MAO A inhibitory component. Cannabis and ondansetron withdrawal were neither associated with anxiety or change in tribulin levels. The investigation supports the postulated role of tribulin as an endogenous correlate of anxiety, its MAO A inhibitory component accounting for a major part of this effect.

Workplace deviance among nurses. The influence of work group norms on drug diversion and/or use

This analysis attempts to integrate sociological and nursing perspectives regarding on-the-job drug theft and/or use by nurses. Specifically, it uses interview data, collected from 25 practicing nurses, to illustrate the link between work group norms and these forms of nursing deviance. These data suggest that informal work group norms often differ from formalized administrative guidelines. Under these circumstances, work group norms consistently take precedence and thus, serve to shape nurses' behaviors.

The electrophysiologic effects of volatile anesthetics and sufentanil on the normal atrioventricular conduction system and accessory pathways in Wolff-Parkinson-White syndrome

BACKGROUND

The effects of volatile agents and sufentanil anesthesia on the electrophysiologic properties of the accessory pathway and on the incidence of intraoperative tachyarrhythmias in patients with Wolff-Parkinson-White syndrome are unknown. Therefore, we studied these agents for their use in patients undergoing ablative procedures or requiring a general anesthetic for other surgeries.

METHODS

Twenty-one patients with Wolff-Parkinson-White syndrome undergoing surgical ablation were anesthetized with sufentanil (20 micrograms/kg), lorazepam (0.06 mg/kg), and vecuronium (20 mg). After sternotomy, the electrophysiologic study during antegrade stimulation consisted of the effective refractory period of the right atrium, atrioventricular node, and accessory pathway; the shortest cycle length of the atrioventricular node and accessory pathway; and the coupling interval. During retrograde stimulation, the effective refractory period of the right ventricle and accessory pathway and the shortest cycle length of the accessory pathway were measured and compared to preoperative electrophysiologic values. Patients then were randomized to receive 1 MAC of halothane, isoflurane, or enflurane, and the electrophysiologic study was repeated.

RESULTS

Sufentanil-lorazepam caused mild prolongation (P < 0.05) of the effective refractory period of the accessory pathway and the shortest cycle length of the atrioventricular node. Enflurane and isoflurane significantly prolonged all parameters related to refractoriness during antegrade conduction, with enflurane having the largest effect. During retrograde conduction, isoflurane prolonged the effective refractory period of the right ventricle and accessory pathway and the shortest cycle length of the accessory pathway, whereas enflurane prolonged only the accessory pathway effective refractory period and shortest cycle length. Halothane had the least effect on refractoriness, causing significant prolongation of the atrioventricular node effective refractory period and the shortest cycle length of the accessory pathway only during antegrade conduction. The coupling interval, a measure of the period of vulnerability to supraventricular tachycardia, was prolonged only by halothane and isoflurane. Supraventricular tachycardia was still obtainable in all patients.

CONCLUSIONS

Sufentanil-lorazepam has no clinically significant effect on the electrophysiologic expression of the accessory pathway. Of the volatile agents, enflurane most, isoflurane next, and halothane least increased refractoriness within the accessory and atrioventricular pathways. Therefore, administration of these volatile agents during ablative procedures may confound interpretation of postablative studies used to determine the success of ablation treatment. Conversely, in patients with preexcitation syndrome requiring general anesthesia for nonablative procedures, volatile agents may reduce the incidence of perioperative tachyarrhythmias because of their effects on refractoriness. Enflurane would be the agent of choice because it increases refractoriness the most without prolonging the coupling interval.

Evaluation of the abuse potential of the novel analgesic flupirtine maleate

To evaluate the psychopharmacological effects and potential abuse liability of the novel analgesic flupirtine maleate the subjective and behavioral effects of orally administered flupirtine, lorazepam and placebo were studied in polydrug abusers. Effects were measured before and for 6 h after drug administration under double-blind conditions. At therapeutic doses flupirtine was not differentiated from placebo. Lorazepam and higher doses of flupirtine produced increases in subject-rated liking, ARCI MBG scale scores, and sedative-like effects including impaired psychomotor performance. Flupirtine, but not lorazepam, increased ratings on measures indicating dysphoric effects. The results indicate that flupirtine has some sedative-like effects but that its abuse potential is probably modest.

Anesthetic requirements during electromagnetic extracorporeal shock wave lithotripsy

An important aspect of modern extracorporeal shock wave lithotripsy is the ability to perform the procedure without anesthesia. Between June 1987 and April 1990, a total of 7,500 treatments were performed in our Lithotripsy Unit, using the Lithostar (Siemens AG, Erlangen, FRG): moreover 80% of the treatments were carried out as an anesthesia-free outpatient service. All treatments were reviewed for anesthetic requirements. Epidural anesthesia was performed in 74/7,500 (0.98%) treatments: during the initial period, the first 70 procedures were systematically performed under epidural anesthesia, and in 4 later cases of simultaneous endoscopic stone manipulation. Local skin infiltration was applied at the coupling site in 658/7,500 (8.7%) treatments. With increasing experience and technological improvement, 6,229/7,500 (83%) procedures were performed later on with only mild sedation: 1 mg of lorazepam orally 30 min before the treatment. Intravenous sedation was required in 510/7,500 (6.8%) cases because of painful local irritation, especially when treating calculi close to sites where shock waves can progress along the ribs. General anesthesia was required in all 28 children (0.4%).

Arterial oxygen saturation following premedication for cardiac surgery

We studied patients scheduled for coronary artery bypass surgery following premedication with lorazepam, morphine and droperidol, using pulse oximetry and serial electrocardiographic (ECG) recordings. Arterial oxygen saturation (SaO2) values were compared with those obtained during two control periods when the patients were awake and asleep. All patients demonstrated progressive arterial oxygen desaturation during the premedication period, statistically significant from both controls (P less than 0.001). Twelve of the 15 patients developed hypoxaemia or severe hypoxaemia which was corrected immediately by administration of oxygen. New ECG changes developed during the premedication period in 33% of patients. It is concluded that additional oxygen should be administered to patients receiving this and similar premedication regimens.

Alfentanil plasma concentration v. effect relationships in cardiac surgical patients

Effects of alfentanil, preceded by lorazepam, on suppression of haemodynamic and somatic responses to noxious stimuli was studied in patients undergoing CABG. Plasma concentration of alfentanil, somatic and haemodynamic responses were measured at loss of consciousness, tracheal intubation, sternotomy and during multiple application of electrocoagulation. Additional alfentanil was administered i.v. to control unwanted responses. Study 1 (six patients): lorazepam 0.08 mg kg-1 by mouth 1-2 h before operation, alfentanil priming infusion (60 micrograms kg-1 min-1 for 10 min) followed by maintenance infusion (4.5 micrograms kg-1 min-1). With mean plasma alfentanil 1178 (SEM 54) ng ml-1, two patients required supplementary alfentanil to suppress somatic motor responses; one patients required nitroglycerin to control an increase in arterial pressure which was unresponsive to additional alfentanil following sternotomy. Study 2 (13 patients): lorazepam 0.04 mg kg-1 by mouth as premedication; one of three maintenance infusion rates of alfentanil: 5.4 (n = 4), 6.6 (n = 5), or 7.8 (n = 4) micrograms kg-1 min-1, each preceded by a proportional priming infusion. With plasma alfentanil 2181 (62) ng ml-1, somatic motor responses requiring additional alfentanil occurred in nine patients; haemodynamic responses in four of seven patients tested could not be controlled by alfentanil. The highest plasma concentration of alfentanil to prevent response to a stimulus other than tracheal intubation was different between the two studies (P less than 0.05). We conclude that alfentanil alone is insufficient to suppress haemodynamic and somatic motor responses to noxious stimulation during CABG and that the role of premedication is significant.

Comparative study of the abuse liability of alprazolam, lorazepam, diazepam, methaqualone, and placebo

Subjective effects of two benzodiazepines--alprazolam and lorazepam--were compared with two drugs of known abuse potential--diazepam and methaqualone--and placebo. This double-blind, crossover trial tested 30 casual recreational sedative users in a seminaturalistic setting. Methaqualone was more euphoriant and less sedative than the benzodiazepines. Diazepam and lorazepam were more euphoriant than placebo; alprazolam's euphoriant effect did not differ from these treatments. On other measures of abuse liability the benzodiazepines rated similarly, diazepam rating highest.

Benzodiazepine dependent patients and their psychological treatment

1. 91 patients were referred to a tranquilizer withdrawal clinic. 44 of these entered a withdrawal programme. The characteristics of the patients are described. 2. 72% of patients accepted for benzodiazepine withdrawal had a history of previous psychiatric contact. They also had significantly higher scores on S.T.A.I. than control groups of non-psychotic psychiatric out-patients indicating a considerable psychiatric morbidity prior to withdrawal. 3. 12 patients were treated with psychological group therapy using anxiety management techniques. The outcome of this pilot study showed that 50% of subjects were able to discontinue their benzodiazepines despite previous failures. 4. Patients found learning to cope with symptoms, sharing problems with others and learning to change thoughts the most useful components of the anxiety management package during withdrawal.

Rapid induction of lorazepam dependence and reversal with flumazenil

Benzodiazepine tolerance, dependence and withdrawal are well established clinical entities although the pharmacological basis for these are still unclear. Recent data suggest that the primary event may be a change in efficacy at the benzodiazepine receptor. The present study demonstrates the rapid development of tolerance and dependence to lorazepam, defines its pharmacology in more detail, and shows that it may be rapidly reversed by treatment with the benzodiazepine antagonist flumazenil. These observations argue in favour of a receptor efficacy change underlying benzodiazepine tolerance and withdrawal and suggest a potential pharmacological treatment for this common and disabling clinical problem.

The incidence of awareness, and amnesia for perioperative events, after cardiac surgery with lorazepam and fentanyl anesthesia

One hundred patients (mean age 59 +/- 10 years) were premedicated with morphine, 0.15 mg/kg, and scopolamine, 0.008 mg/kg. Anesthesia was induced with lorazepam, 50 microg/kg, followed by fentanyl, 50 microg/kg, oxygen and pancuronium, 0.15 mg/kg. Isoflurane was given for short periods before and after cardiopulmonary bypass to 57 patients when hypertension was uncontrolled by addition of fentanyl and/or nitroglycerin. Morphine was used as the sole sedative postoperatively. Patients were interviewed following discharge from the surgical intensive care unit to assess the incidence of operative awareness, and to assess amnesia for events occurring during four preoperative and two postoperative periods of the patients' hospital stay. During three preoperative periods (day of admission, evening before, and morning before operation), 1%, 3%, and 2% of patients had complete amnesia, and 19%, 41%, and 31% had partial amnesia of events. Fifty-five percent of patients exhibited complete, and 34% of patients exhibited partial amnesia to events occurring in the preinduction period. Two patients reported intraoperative awareness (noises, conversation) occurring at the end of the anesthetic. In the two postoperative periods (morning of the day after surgery and intensive care stay), 9% and 15% of patients had complete, and 35% and 47% of patients exhibited partial amnesia. Amnesia was statistically significantly greater in patients over 60 years of age in the preinduction period. Duration of cardiopulmonary bypass did not affect the incidence of amnesia.

II: Patients premedicated with lorazepam

The infusion rate of propofol required to supplement 67% nitrous oxide in oxygen to maintain surgical anaesthesia was determined in 72 patients premedicated with lorazepam. Following an induction dose of propofol 2 mg kg-1, groups of eight patients received an infusion of propofol varying from 60 to 200 micrograms kg-1 min-1. Probit analysis was used to determine the ED50 (130 micrograms kg-1 min-1; 95% confidence limits: 106-167 micrograms kg-1 min-1) and ED95 (348 micrograms kg-1 min-1; 95% confidence limits: 233-1296 micrograms kg-1 min-1) for propofol infusion. Whole blood propofol concentrations at the time of surgical incision correlated strongly with the infusion rate, giving an EC50 value of 2.5 micrograms ml-1, and an EC95 value of 5.92 micrograms ml-1. There was no significant correlation between the rate of infusion of propofol, or the total propofol dose, and the times to response to command, or to recall of birthdate.