A Comparative Study on Intranasal Versus Intravenous Lorazepam in the Management of Acute Seizure in Children.

INTRODUCTION: The acute seizure in childhood is a medical emergency which is usually managed by benzodiazepines used as a first line of therapy. There are no strict guidelines of using intranasal lorazepam in India. Many paediatricians use it in an emergency situation as it is inexpensive, easy to administer and even treatment can be started at home. Very few studies are available to compare efficacy and safety of intravenous lorazepam with intranasal lorazepam in childhood seizure, though both routes have comparable pharmacokinetic profile. Intravenous lorazepam (0.1 mg/kg) is already recommended as a first-line treatment of acute childhood seizures in India. There are very few studies regarding the usefulness of intranasal lorazepam. With this background, we compared intranasal lorazepam with the more widely accepted intravenous lorazepam for control of acute seizure. AIM: To compare effectiveness and safety of intranasal and intravenous lorazepam in acute seizure in children aged 5-12 years. MATERIALS AND METHODS: This is an analytical observational cross-sectional study involving patients with acute seizure who received lorazepam via either the intravenous or intranasal route. Formulation and dosage of lorazepam were the same in both routes. RESULTS: Distributions of patient groups according to sex, age, and weight were statistically not significant (p=0.42, p=0.391, and p=0.605, respectively). Time to control seizure within 10 min and persistent cessation of seizure activity were similar in both groups. Safety parameters showed no differences statistically. CONCLUSIONS: Though intravenous lorazepam is recommended as first-line treatment, intranasal lorazepam may be a good alternative choice in a convulsing child.

Construction and Verification of Physiologically Based Pharmacokinetic Models for Four Drugs Majorly Cleared by Glucuronidation: Lorazepam, Oxazepam, Naloxone, and Zidovudine.

Physiologically based pharmacokinetic (PBPK) modeling is less well established for substrates of UDP-glucuronosyltransferases (UGT) than for cytochrome P450 (CYP) metabolized drugs and more verification of simulations is necessary to increase confidence. To address specific challenges of UGT substrates, we developed PBPK models for four drugs cleared majorly via glucuronidation (lorazepam, oxazepam, naloxone, and zidovudine). In vitro to in vivo scaling of intrinsic clearance generated with co-cultured human hepatocytes was applied for hepatic metabolism and extra-hepatic clearance was extrapolated based on relative expression of UGT isoforms in the liver, kidney, and intestine. Non-metabolic clearance and the contributions of individual UGT isoforms to glucuronidation were based on in vitro and in vivo studies taken from the literature and simulations were verified and evaluated with a broad set of clinical pharmacokinetic data. Model evaluation showed systemic clearance predictions within 1.5-fold for all drugs and all simulated parameters were within 2-fold of observed. However, during the verification step, top-down model fitting was necessary to adjust for under-prediction of zidovudine VSS and renal clearance and over estimation of intestinal first pass for lorazepam, oxazepam, and zidovudine. The impact of UGT2B15 polymorphisms on the pharmacokinetics of oxazepam and lorazepam was simulated and glucuronide metabolites were also simulated for all four drugs. To increase confidence in predicting extra-hepatic clearance, improvement of enzyme phenotyping for UGT substrates and more quantitative tissue expression levels of UGT enzymes are both needed. Prediction of glucuronide disposition is also challenging when active transport processes play a major role.

In-vitro and in-vivo evaluation of chitosan-based thermosensitive gel containing lorazepam NLCs for the treatment of status epilepticus.

The objective of this study was to develop an in-situ gel containing lorazepam (LZM) loaded nanostructured lipid carriers (NLCs) for direct nose-to-brain delivery in order to increase drug therapeutic efficacy in the treatment of epilepsy. Accordingly, LZM loaded NLCs were formulated using emulsification solvent diffusion and evaporation method; then the effects of the formulation variables on different physicochemical characteristics of NLCs were investigated. Thermosensitive in-situ gels containing LZM-NLCs were prepared using a combination of chitosan and ß-glycerol phosphate (ß-GP). The anticonvulsant efficacy of LZM-NLCs-Gel was then examined using the pentylenetetrazole (PTZ) model. The optimised NLCs were spherical, showing the particle size of 71.70 ± 5.16 nm and the zeta potential of -20.06 ± 2.70 mV. The pH and gelation time for the chitosan solution with 15% (w/v) ß-GP were determined to be 7.12 ± 0.03 and 5.33 ± 0.58 min, respectively. The in-vivo findings showed that compared with the control group and the group that received LZM-Gel, the occurrence of PTZ-induced seizures in the rats was significantly reduced by LZM-NLCs-Gel after intranasal administration. These results, therefore, suggested that the LZM-NLCs-Gel system could have potential applications for brain targeting through nasal route and might increase LZM therapeutic efficacy in the treatment of epilepsy.

Intranasal Lorazepam for Treatment of Severe Agitation in a Pediatric Behavioral Health Patient in the Emergency Department.

The treatment of severe agitation, aggression, and violent behavior in behavioral health patients who present to the emergency department (ED) often requires the intramuscular administration of a sedative. However, administering an intramuscular sedative to an uncooperative patient is associated with the risk of needlestick injuries to both patients and health care providers, and times to onset of sedation range from 15 to 45 minutes. Intranasal absorption is more rapid than intramuscular, with sedatives such as lorazepam reaching peak serum concentrations up to 6 times faster when administered intranasally. We present the first report of using intranasal lorazepam as a needle-free method of providing rapid and effective sedation to treat severe agitation in a pediatric behavioral health patient presenting to the ED.

Organ distribution of diclazepam, pyrazolam and 3-fluorophenmetrazine.

The organ distribution of 3-fluorophenmetrazine (3-FPM), pyrazolam, diclazepam as well as its main metabolites delorazepam, lormetazepam and lorazepam, was investigated. A solid phase extraction (SPE) and a QuEChERS (acronym for quick, easy, cheap, effective, rugged and safe) - approach were used for the extraction of the analytes from human tissues, body fluids and stomach contents. The detection was performed on a liquid chromatography-tandem mass spectrometry system (LCMS/MS). The analytes of interest were detected in all body fluids and tissues. Results showed femoral blood concentrations of 10 µg/L for 3-FPM, 28 µg/L for pyrazolam, 1 µg/L for diclazepam, 100 µg/L for delorazepam, 6 µg/L for lormetazepam, and 22 µg/L for lorazepam. Tissues (muscle, kidney and liver) and bile exhibited higher concentrations of the mentioned analytes than in blood. Additional positive findings in femoral blood were for 2-fluoroamphetamine (2-FA, approx. 89 µg/L), 2-flourometamphetamine (2-FMA, hint), methiopropamine (approx. 2.2 µg/L), amphetamine (approx. 21 µg/L) and caffeine (positive). Delorazepam showed the highest ratio of heart (C) and femoral blood (P) concentration (C/P ratio = 2.5), supported by the concentrations detected in psoas muscle (430 µg/kg) and stomach content (approx. 210 µg/L, absolute 84 µg). The C/P ratio indicates that delorazepam displays susceptibility for post-mortem redistribution (PMR), supported by the findings in muscle tissue. 3-FPM, pyrazolam, diclazepam, lorazepam and lormetazepam did apparently not exhibit any PMR. The cause of death, in conjunction with autopsy findings was concluded as a positional asphyxia promoted by poly-drug intoxication by arising from designer benzodiazepines and the presence of synthetic stimulants.

Application of a physiologically based pharmacokinetic model for the prediction of mirabegron plasma concentrations in a population with severe renal impairment.

We previously verified a physiologically based pharmacokinetic (PBPK) model for mirabegron in healthy subjects using the Simcyp Simulator by incorporating data on the inhibitory effect on cytochrome P450 (CYP) 2D6 and a multi-elimination pathway mediated by CYP3A4, uridine 5'-diphosphate-glucuronosyltransferase (UGT) 2B7 and butyrylcholinesterase (BChE). The aim of this study was to use this PBPK model to assess the magnitude of drug-drug interactions (DDIs) in an elderly population with severe renal impairment (sRI), which has not been evaluated in clinical trials. We first determined the system parameters, and meta-analyses of literature data suggested that the abundance of UGT2B7 and the BChE activity in an elderly population with sRI was almost equivalent to and 20% lower than that in healthy young subjects, respectively. Other parameters, such as the CYP3A4 abundance, for an sRI population were used according to those built into the Simcyp Simulator. Second, we confirmed that the PBPK model reproduced the plasma concentration-time profile for mirabegron in an sRI population (simulated area under the plasma concentration-time curve (AUC) was within 1.5-times that of the observed value). Finally, we applied the PBPK model to simulate DDIs in an sRI population. The PBPK model predicted that the AUC for mirabegron with itraconazole (a CYP3A4 inhibitor) was 4.12-times that in healthy elderly subjects administered mirabegron alone, and predicted that the proportional change in AUC for desipramine (a CYP2D6 substrate) with mirabegron was greater than that in healthy subjects. In conclusion, the PBPK model was verified for the purpose of DDI assessment in an elderly population with sRI.

Potential prediction of formulation performance in paediatric patients using biopharmaceutical tools and simulation of clinically relevant administration scenarios of nifedipine and lorazepam.

AIMS: This study explores the impact of paediatric patient related factors and choice of formulation on the dissolution characteristics of nifedipine and lorazepam, 2 drug substances regularly applied in very young patients and in compounded formulations. METHODS: Dissolution experiments were designed to reflect clinical practice in a paediatric hospital, with respect to dosage forms, feeding regimens and methods of administration. Solubility studies addressed the influence of age and prandial state. Drug solubility and dissolution experiments were conducted in biorelevant media and adapted age-specific (neonate and infant) media. Dissolution studies were performed with the mini-paddle apparatus and the flow-through cell apparatus. RESULTS: Dissolution of nifedipine formulations was not affected by age-related changes of the fasted state simulated gastrointestinal fluids, and by disintegration of the formulation before administration. However, a significant difference in nifedipine's dissolution rate from commercial tablets and compounded capsules was observed. The dissolution of lorazepam tablets was affected by fasted- vs fed-state media, but it was deemed less likely to be clinically relevant. The significant effect of fed-state media on nifedipine's solubility was considered to have possible clinical relevance since very young patients are almost continuously in a fed state. CONCLUSION: The in vitro results obtained from these studies reveal the potential of biorelevant solubility and dissolution studies reflecting clinical practice to predict drug performance in paediatric patients.

Development of a Korean-specific virtual population for physiologically based pharmacokinetic modelling and simulation.

Physiologically based pharmacokinetic (PBPK) modelling and simulation is a useful tool in predicting the PK profiles of a drug, assessing the effects of covariates such as demographics, ethnicity, genetic polymorphisms and disease status on the PK, and evaluating the potential of drug-drug interactions. We developed a Korean-specific virtual population for the SimCYP® Simulator (version 15 used) and evaluated the population's predictive performance using six substrate drugs (midazolam, S-warfarin, metoprolol, omeprazole, lorazepam and rosuvastatin) of five major drug metabolizing enzymes (DMEs) and two transporters. Forty-three parameters including the proportion of phenotypes in DMEs and transporters were incorporated into the Korean-specific virtual population. The simulated concentration-time profiles in Koreans were overlapped with most of the observed concentrations for the selected substrate drugs with a < 2-fold difference in clearance. Furthermore, we found some drug models within the SimCYP® library can be improved, e.g., the minor allele frequency of ABCG2 and the fraction metabolized by UGT2B15 should be incorporated for rosuvastatin and lorazepam, respectively. The Korean-specific population can be used to evaluate the impact of ethnicity on the PKs of a drug, particularly in various stages of drug development.

Endoscopic removal of a gastric pharmacobezoar induced by clomipramine, lorazepam, and domperidone overdose: a case report.

INTRODUCTION: Gastric pharmacobezoars are a rare entity that can induce mechanical gastric outlet obstructions and sometimes prolong toxic pharmacological effects. Certain medications, such as sustained-release forms, contain cellulose derivatives that may contribute to the adhesion between pills and lead to the creation of an aggregate resulting in a pharmacobezoar. Case reports are rare, and official guidelines are needed to help medical teams choose proper treatment options. CASE PRESENTATION: Our patient was a 40-year-old Caucasian woman with borderline personality disorder and active suicidal thoughts who was found unconscious after a massive drug consumption of slow-release clomipramine, lorazepam, and domperidone. On her arrival in the emergency room, endotracheal intubation was preformed to protect her airway, and a chest x-ray revealed multiple coffee grain-sized opaque masses in the stomach. She was treated with activated charcoal followed by two endoscopic gastric decontaminations 12 h apart in order to extract a massive gastric pharmacobezoar by manual removal of the tablets. CONCLUSION: This case demonstrates that in the case of a massive drug consumption, a pharmacobezoar should be suspected, particularly when cellulose-coated pills are ingested. Severe poisoning due to delayed drug release from the gastric aggregate is a potential complication. Detection by x-ray is crucial, and treatment is centered on removal of the aggregate. The technique of decontamination varies among experts, and no formal recommendations exist to date. It seems reasonable that endoscopic evaluation should be performed in order to determine the appropriate technique of decontamination. Care should be patient-oriented and take into account the clinical presentation and any organ failure, and it should not be determined solely by the suspected medication ingested. Thus, serum levels are not sufficient to guide management of tricyclic antidepressant intoxication.

Altered Pharmacokinetics in Prolonged Infusions of Sedatives and Analgesics Among Adult Critically Ill Patients: A Systematic Review.

PURPOSE: The pharmacokinetic (PK) parameters of many drugs are altered as a consequence of the pathophysiological changes associated with critical illness. The critically ill population presents challenges when titrating infusions of sedatives and analgesics to maintain optimal sedation and pain levels. This systematic review examined the PK data in critically ill adult patients with prolonged infusions (>24 hours) of commonly used sedatives and analgesics to highlight possible altered PK parameters compared with noncritically ill patients. METHODS: A literature search of PK studies was performed by using MEDLINE (1946-December 2017) and EMBASE (1910-December 2017); we identified further studies by citation tracking (Web of Science) and checked references of retrieved studies and review articles. All studies were included that were published in English, Chinese, or German; conducted in critically ill adult patients receiving lorazepam, midazolam, propofol, dexmedetomidine, sufentanil, alfentanil, remifentanil, morphine, or fentanyl infusion for ≥24 hours; and reported PK parameters. When appropriate, we conducted a meta-analysis on volume of distribution at steady state (Vdss) (liters), clearance (Cl) (liters per hour), and elimination t1/2 (hours) by using a DerSimonian-Laird random effects model to estimate the summary mean and 95% CIs. Results were compared with commonly reported PK ranges in 70-kg noncritically ill patients. FINDINGS: Thirty-three randomized controlled trials and prospective cohort studies were identified involving 1803 adult critically ill patients with 35 drug treatment arms: fifteen midazolam (n = 906) studies, three dexmedetomidine (n = 561), nine propofol (n = 165), four lorazepam (n = 86), one morphine (n = 20), two remifentanil (n = 55), and one sufentanil (n = 10). Each study showed large variations in Vdss, Cl, and elimination t1/2 within and between individual participants. High clinical and methodical heterogeneity between the dexmedetomidine studies prevented the direct comparison of PK parameters between critically ill and noncritically ill patients. Use of midazolam, propofol, and lorazepam in critically ill patients was associated with at least a 2- to 4-fold increase in Vdss compared with noncritically ill patients; Cl decreased ∼2-fold for midazolam and 10-fold for morphine. Critically ill patients receiving prolonged infusions of midazolam, propofol, remifentanil, and sufentanil had at least 2-fold longer elimination or terminal t1/2 than noncritically ill patients. IMPLICATIONS: These findings show a marked difference in many PK parameters from those reported for noncritically ill patients. Initiatives to improve the delivery of prolonged sedatives and analgesic infusions should be informed by PK parameters (Vdss, context-sensitive t1/2, and elimination t1/2) and data derived from critically ill patients.

Population Pharmacokinetics and Exploratory Exposure-Response Relationships of Diazepam in Children Treated for Status Epilepticus.

Diazepam is labeled for status epilepticus (SE) in children, but there are limited data characterizing its disposition in pediatric patients. We developed a population pharmacokinetic (PK) model of i.v. diazepam in children with SE. We evaluated relationships between PK parameters and both safety and efficacy, and simulated exposures using dosing regimens from the product label and clinical practice. The model was developed using prospective data from a pediatric clinical trial comparing diazepam to lorazepam for treatment of SE. Altogether, 87 patients aged ≥ 3 months to < 18 years contributed 162 diazepam concentrations. Diazepam PKs were well characterized by a two-compartment model scaled by body size. No significant or clinically important relationships were observed between diazepam PKs and safety or efficacy. Simulations demonstrated that, compared with label dosing, the study dose (0.2 mg/kg i.v., maximum 8 mg) resulted in greater frequency in rapidly achieving the target therapeutic range of 200-600 ng/mL.

Evaluation of IV to Enteral Benzodiazepine Conversion Calculations in a Pediatric Intensive Care Setting.

OBJECTIVES: To evaluate if institutionally established calculations for transitioning continuous IV midazolam to enteral benzodiazepines maintain Withdrawal Assessment Tool-Version 1 scores equal to or less than preconversion values. DESIGN: Retrospective cohort study evaluating the effectiveness and safety of benzodiazepine conversion calculations embedded within an institution-specific clinical pathway for sedation and weaning of mechanically ventilated pediatric patients. SETTING: A 55-bed, mixed-medical, noncardiac surgical PICU in a tertiary care children's hospital. PATIENTS: All patients age 6 months to 18 years who received continuous midazolam for 5 days or longer while mechanically ventilated for 5-21 days and were then converted to either enteral diazepam or lorazepam following extubation (or return to baseline ventilator settings in tracheostomy-dependent patients) between January 1, 2015, and June 30, 2016. INTERVENTIONS: Benzodiazepine conversion calculations were applied according to institutional clinical pathway guidance. MEASUREMENTS AND MAIN RESULTS: Withdrawal Assessment Tool-Version 1 scores were compared pre and post benzodiazepine conversion. Patient demographics, benzodiazepine dose escalations, as needed benzodiazepine requirements, and severe adverse events within 48 hours of conversion were assessed. Seventy-one patient encounters were analyzed (median age, 2.5 yr; interquartile range, 1.2-5.3). The median Withdrawal Assessment Tool-Version 1 scores pre conversion and post conversion were not significantly different (1 [interquartile range, 0.75-2] and 1 [interquartile range, 0.25-2], respectively, p = 0.1). As needed benzodiazepine doses were administered in 38% of encounters post conversion, but escalation of a scheduled enteral benzodiazepine regimen was only required in 2.8% of encounters. Post conversion, one patient (1.4%) had increased seizure activity, and four patients (5.6%) required fluid boluses secondary to tachycardia or dehydration, but not hypotension. CONCLUSIONS: These findings suggest that standardized benzodiazepine conversions successfully achieved consistent Withdrawal Assessment Tool-Version 1 scores compared with preconversion values. Severe adverse events associated with oversedation and/or withdrawal were minimal and confounded by underlying disease states.

Sedative Plasma Concentrations and Delirium Risk in Critical Illness.

BACKGROUND: The relationship between plasma concentration of sedatives and delirium is unknown. OBJECTIVE: We hypothesized that higher plasma concentrations of lorazepam are associated with increased delirium risk, whereas higher plasma concentrations of dexmedetomidine are associated with reduced delirium risk. METHODS: This prospective cohort study was embedded in a double-blind randomized clinical trial, where ventilated patients received infusions of lorazepam and dexmedetomidine. Plasma concentrations of these drugs and delirium assessments were measured at least daily. A multivariable logistic regression model accounting for repeated measures was used to analyze associations between same-day plasma concentrations of lorazepam and dexmedetomidine (exposures) and the likelihood of next-day delirium (outcome), adjusting for same-day mental status (delirium, coma, or normal) and same-day fentanyl doses. RESULTS: This critically ill cohort (n = 103) had a median age of 60 years (IQR: 48-66) with APACHE II score of 28 (interquartile range [IQR] = 24-32), where randomization resulted in assignment to lorazepam (n = 51) or dexmedetomidine (n = 52). After adjusting for same-day fentanyl dose and mental status, higher plasma concentrations of lorazepam were associated with increased probability of next-day delirium (comparing 500 vs 0 ng/mL; odds ratio [OR] = 13.2; 95% CI = 1.4-120.1; P = 0.02). Plasma concentrations of dexmedetomidine were not associated with next-day delirium (comparing 1 vs 0 ng/mL; OR = 1.1; 95% CI = 0.9-1.3; P = 0.45). CONCLUSIONS: In critically ill patients, higher lorazepam plasma concentrations were associated with delirium, whereas dexmedetomidine plasma concentrations were not. This implies that the reduced delirium risk seen in patients sedated with dexmedetomidine may be a result of avoidance of benzodiazepines, rather than a dose-dependent protective effect of dexmedetomidine.

Population Pharmacokinetic/ Pharmacodynamic Modelling of Auditory-Evoked Event-Related Potentials with Lorazepam.

Event-related potentials (ERPs) are commonly used in Neuroscience research, particularly the P3 waveform because it is associated with cognitive brain functions and is easily elicited by auditory or sensory inputs. ERPs are affected by drugs such as lorazepam, which increase the latency and decrease the amplitude of the P3 wave. In this study, auditory-evoked ERPs were generated in 13 older healthy volunteers using an oddball tone paradigm, after administration of single 0.5 and 2 mg doses of lorazepam. Population pharmacokinetics (PK)/pharmacodynamics (PD) models were developed using nonlinear mixed-effects methods in order to assess the effect of lorazepam on the latency and amplitude of the P3 waveforms. The PK/PD models showed that doses of 0.3 mg of lorazepam achieved approximately half of the maximum effect on the latency of the P3 waveform. For P3 amplitude, half the maximum effect was achieved with a dose of 1.2 mg of lorazepam. The PK/PD models also predicted an efficacious dose range of lorazepam, which was close to the recommended therapeutic range. The use of longitudinal P3 latency data allowed better predictions of the lorazepam efficacious dose range than P3 amplitude or aggregate exposure-response data, suggesting that latency could be a more sensitive parameter for drugs with similar mechanisms of action as lorazepam and that time course rather than single time-point ERP data should be collected. Overall, the results suggest that P3 ERP waveforms could be used as potential non-specific biomarkers for functional target engagement for drugs with brain activity, and PK/PD models can aid trial design and choice of doses for development of new drugs with ERP activity.

Population Pharmacokinetics and Exploratory Pharmacodynamics of Lorazepam in Pediatric Status Epilepticus.

BACKGROUND: Lorazepam is one of the preferred agents used for intravenous treatment of status epilepticus (SE). We combined data from two pediatric clinical trials to characterize the population pharmacokinetics of intravenous lorazepam in infants and children aged 3 months to 17 years with active SE or a history of SE. METHODS: We developed a population pharmacokinetic model for lorazepam using the NONMEM software. We then assessed exploratory exposure-response relationships using the overall efficacy and safety study endpoints, and performed dosing simulations. RESULTS: A total of 145 patients contributed 439 pharmacokinetic samples. The median (range) age and dose were 5.4 years (0.3-17.8) and 0.10 mg/kg (0.02-0.18), respectively. A two-compartment pharmacokinetic model with allometric scaling described the data well. In addition to total body weight (WT), younger age was associated with slightly higher weight-normalized clearance (CL). The following relationships characterized the typical values for the central compartment volume (V1), CL, peripheral compartment volume (V2), and intercompartmental CL (Q), using individual subject WT (kg) and age (years): V1 (L) = 0.879*WT; CL (L/h) = 0.115*(Age/4.7)0.133*WT0.75; V2 (L) = 0.542*V1; Q (L/h) = 1.45*WT0.75. No pharmacokinetic parameters were associated with clinical outcomes. Simulations suggest uniform pediatric dosing (0.1 mg/kg, to a maximum of 4 mg) can be used to achieve concentrations of 50-100 ng/mL in children with SE, which have been previously associated with effective seizure control. CONCLUSIONS: The population pharmacokinetics of lorazepam were successfully described using a sparse sampling approach and a two-compartment model in pediatric patients with active SE.

Adverse performance effects of acute lorazepam administration in elderly long-term users: pharmacokinetic and clinical predictors.

BACKGROUND: The benzodiazepine lorazepam is widely utilized in the treatment of elderly individuals with anxiety disorders and related conditions. Negative effects of acute lorazepam administration on cognitive performance, especially memory, have been reported in both previously untreated elderly and in individuals who have received short term (up to three weeks) treatment with therapeutic doses. However, it remains unclear if these adverse cognitive effects also persist after long-term use, which is frequently found in clinical practice. METHODS: Cognitively intact elderly individuals (n=37) on long-term (at least three months) daily treatment with lorazepam were studied using a double-blind placebo-controlled cross-over study design. Subjects were administered their highest daily unit dose of lorazepam (0.25-3.00 mg) or placebo on different days, approximately 1 week apart in a random order, and were assessed on memory, psychomotor speed, and subjective mood states. RESULTS: Subjects had significantly poorer recall and slowed psychomotor performance following acute lorazepam administration. There were no significant effects on self-ratings of mood, sedation, or anxiety in the whole group, but secondary analyses suggested a differential response in subjects with Generalized Anxiety Disorder. CONCLUSIONS: The reduced recall and psychomotor slowing that we observed, along with an absence of significant therapeutic benefits, following acute lorazepam administration in elderly long-term users reinforces the importance of cognitive toxicity as a clinical factor in benzodiazepine use, especially in this population.

The effect of experimentally induced sleep disturbance on the pharmacokinetics of lorazepam in healthy volunteers.

The aim of this study was to evaluate the effect of sleep disturbance on the pharmacokinetics, especially on the absorption, of lorazepam in humans. Eight healthy male volunteers received a single oral dose of lorazepam 1 mg before sleep on two occasions in a cross-over design. In either of the two doses, subjects were intermittently exposed to noise for 1.5 hours after oral lorazepam administration. Plasma lorazepam concentrations were measured by HPLC. The exposure to noise significantly prolonged tmax (control vs. noise: 2.0 vs. 3.0 hours) and significantly decreased AUC of lorazepam in the absorption phase. The reduction was 54% (95% CI, 15 - 75%) and 24% (3 - 40%) for AUC (0 - 1 hours) and AUC (0 - 3 hours), respectively. No significant changes were observed in other pharmacokinetic parameters. The results of this study suggest that the onset of drug action after oral lorazepam administration can be altered by sleep disturbance.