Development of a pharmacokinetic and pharmacodynamic model for intranasal administration of midazolam in older adults: a single-site two-period crossover study

BACKGROUND

Intranasal midazolam can produce procedural sedation in frail older patients with dementia who are unable to tolerate necessary medical or dental procedures during domiciliary medical care. Little is known about the pharmacokinetics and pharmacodynamics of intranasal midazolam in older (>65 yr old) people. The aim of this study was to understand the pharmacokinetic/pharmacodynamic properties of intranasal midazolam in older people with the primary goal of developing a pharmacokinetic/pharmacodynamic model to facilitate safer domiciliary sedation care.

METHODS

We recruited 12 volunteers: ASA physical status 1-2, aged 65-80 yr, and received midazolam 5 mg intravenously and 5 mg intranasally on two study days separated by a 6 day washout period. Concentrations of venous midazolam and 1'-OH-midazolam, Modified Observer's Assessment of Alertness/Sedation (MOAA/S) score, bispectral index (BIS), arterial pressure, ECG, and respiratory parameters were measured for 10 h.

RESULTS

Time to peak effect of intranasal midazolam for BIS, MAP, and SpO₂ were 31.9 (6.2), 41.0 (7.6), and 23.1 (3.0) min, respectively. Intranasal bioavailability was lower compared with intravenous administration (F_abs 95%; 95% confidence interval: 89-100%). A three-compartment model best described midazolam pharmacokinetics following intranasal administration. A separate effect compartment linked to the dose compartment best described an observed time-varying drug-effect difference between intranasal and intravenous midazolam, suggesting direct nose-to-brain transport.

CONCLUSIONS

Intranasal bioavailability was high and sedation onset was rapid, with maximum sedative effects after 32 min. We developed a pharmacokinetic/pharmacodynamic model for intranasal midazolam for older persons and an online tool to simulate changes in MOAA/S, BIS, MAP, and SpO₂ after single and additional intranasal boluses.

CLINICAL TRIAL REGISTRATION

EudraCT (2019-004806-90).

Impact of COVID-19 on Sedation Requirements during Veno-Venous Extracorporeal Membrane Oxygenation for Acute Respiratory Distress Syndrome

COVID-19-associated ARDS (C-ARDS) is mentioned to express higher analgosedation needs, in comparison to ARDS of other etiologies. The objective of this monocentric retrospective cohort study was to compare the analgosedation needs between C-ARDS and non-COVID-19 ARDS (non-C-ARDS) on veno-venous extracorporeal membrane oxygenation (VV-ECMO). Data were collected from the electronic medical records of all adult patients treated with C-ARDS in our Department of Intensive Care Medicine between March 2020 and April 2022. The control group included patients treated with non-C-ARDS between the years 2009 and 2020. A sedation sum score was created in order to describe the overall analgosedation needs. A total of 115 (31.5%) patients with C-ARDS and 250 (68.5%) with non-C-ARDS requiring VV-ECMO therapy were included in the study. The sedation sum score was significantly higher in the C-ARDS group (p < 0.001). COVID-19 was significantly associated with analgosedation in the univariable analysis. By contrast, the multivariable model did not show a significant association between COVID-19 and the sum score. The year of VV-ECMO support, BMI, SAPS II and prone positioning were significantly associated with sedation needs. The potential impact of COVID-19 remains unclear, and further studies are warranted in order to evaluate specific disease characteristics linked with analgesia and sedation.

Treatment of cholinergic-induced status epilepticus with polytherapy targeting GABA and glutamate receptors

Despite new antiseizure medications, the development of cholinergic-induced refractory status epilepticus (RSE) continues to be a therapeutic challenge as pharmacoresistance to benzodiazepines and other antiseizure medications quickly develops. Studies conducted by Epilepsia. 2005;46:142 demonstrated that the initiation and maintenance of cholinergic-induced RSE are associated with trafficking and inactivation of gamma-aminobutyric acid A receptors (GABAA R) thought to contribute to the development of benzodiazepine pharmacoresistance. In addition, Dr. Wasterlain's laboratory reported that increased N-methyl-d-aspartate receptors (NMDAR) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR) contribute to enhanced glutamatergic excitation (Neurobiol Dis. 2013;54:225; Epilepsia. 2013;54:78). Thus, Dr. Wasterlain postulated that targeting both maladaptive responses of reduced inhibition and increased excitation that is associated with cholinergic-induced RSE should improve therapeutic outcome. We currently review studies in several animal models of cholinergic-induced RSE that demonstrate that benzodiazepine monotherapy has reduced efficacy when treatment is delayed and that polytherapy with drugs that include a benzodiazepine (eg midazolam and diazepam) to counter loss of inhibition, concurrent with an NMDA antagonist (eg ketamine) to reduce excitation provide improved efficacy. Improved efficacy with polytherapy against cholinergic-induced seizure is demonstrated by reduction in (1) seizure severity, (2) epileptogenesis, and (3) neurodegeneration compared with monotherapy. Animal models reviewed include pilocarpine-induced seizure in rats, organophosphorus nerve agent (OPNA)-induced seizure in rats, and OPNA-induced seizure in two mouse models: (1) carboxylesterase knockout (Es1-/- ) mice which, similarly to humans, lack plasma carboxylesterase and (2) human acetylcholinesterase knock-in carboxylesterase knockout (KIKO) mice. We also review studies showing that supplementing midazolam and ketamine with a third antiseizure medication (valproate or phenobarbital) that targets a nonbenzodiazepine site rapidly terminates RSE and provides further protection against cholinergic-induced SE. Finally, we review studies on the benefits of simultaneous compared with sequential drug treatments and the clinical implications that lead us to predict improved efficacy of early combination drug therapies. The data generated from seminal rodent studies of efficacious treatment of cholinergic-induced RSE conducted under Dr. Wasterlain's guidance suggest that future clinical trials should treat the inadequate inhibition and temper the excess excitation that characterize RSE and that early combination therapies may provide improved outcome over benzodiazepine monotherapy.

Midazolam for the Successful Treatment of Refractory Spinal-Anesthesia-Associated Hypothermia After Cesarean Delivery

Cesarean deliveries receiving spinal anesthesia with intrathecal morphine are associated with post-operative hypothermia. Lorazepam has been proposed as a reversal agent for treating intrathecal morphine-associated post-cesarean hypothermia. Midazolam is a benzodiazepine familiar to most anesthesia providers and is frequently administered in the perioperative period. We present a post-cesarean delivery spinal anesthesia-associated hypothermia patient successfully treated with intravenous midazolam.

Clinico-Etiological Spectrum and Functional Outcomes of Children with Pre-Status Dystonicus and Status Dystonicus (SD): A Descriptive Study

Background

Status dystonicus (SD) is a life-threatening movement disorder emergency characterized by increasingly frequent and severe episodes of generalized dystonia, requiring urgent hospital admission. The diverse clinico-etiological spectrum, high risk of recurrence, and residual disabilities complicate functional outcomes.

Aim

We aim to describe the clinico-etiological spectrum, radiology, therapeutic options, and follow-up of patients with pre-status dystonicus (pre-SD) and SD.

Methodology

A cross-sectional retrospective study was carried out in a tertiary care referral center. The clinical, laboratory, and radiology data of all patients aged less than 18 years with pre-SD and SD from January 2010 to December 2020 were collected. The Dystonia Severity Assessment Plan (DSAP) scale for grading severity and the modified Rankin Scale (mRS) for assessing outcome were used at the last follow-up visit.

Results

Twenty-eight patients (male:female: 2.1:1) experiencing 33 episodes of acute dystonia exacerbation were identified. The median age at the onset of dystonia and SD presentation was 8.71 (range: 0.25-15.75) and 9.12 (range: 1-16.75) years, respectively. Four patients experienced more than one episode of SD. The etiological spectrum of SD includes metabolic (Wilson's disease-13, L-aromatic amino acid decarboxylase deficiency-one, and Gaucher's disease-one), genetic (neurodegeneration with brain iron accumulation-three and KMT2B and THAP 1 gene-related-one each), structural-three, post-encephalitic sequelae (PES)-four, and immune-mediated (anti-NMDA receptor encephalitis-one). Five patients had pre-SD (DSAP grade 3), and 23 patients had established SD (DSAP grade 4-17 and DSAP grade 5-six). The Rapid escalation of chelation therapy precipitated SD in 11 patients with Wilson's disease. Febrile illness or pneumonia precipitated SD in nine patients. Twenty-three episodes of SD required midazolam infusion in addition to anti-dystonic medications. The median duration of hospital stay was 10 days (range: 3-29). Twenty-three patients had resolution of SD but residual dystonia persisted, while two patients had no residual dystonia at follow-up. Three patients succumbed owing to refractory SD and its complications.

Conclusion

Early identification of triggers, etiology, and appropriate management are essential to calm the dystonic storm.

Overcoming barriers to the management of seizure clusters: ease of use and time to administration of rescue medications

INTRODUCTION

Patients with epilepsy can experience seizure clusters (acute repetitive seizures), defined as intermittent, stereotypic episodes of frequent seizure activity that are distinct from typical seizure patterns. There are three FDA-approved rescue medications, diazepam rectal gel, midazolam nasal spray, and diazepam nasal spray, that can be administered to abort a seizure cluster in a nonmedical, community setting. Despite their effectiveness and safety, rescue medications are underutilized, and patient/caregiver experiences and perceptions of ease of use may constitute a substantial barrier to greater utilization.

AREAS COVERED

The literature on rescue medications for seizure clusters is reviewed, including the effectiveness and safety, with an emphasis on ease and timing of treatment and associated outcomes. Barriers to greater utilization of rescue medication and the role of seizure action plans are discussed.

EXPERT OPINION

Intranasal rescue medications are easier to use and can be administered more rapidly than other routes (rectal, intravenous). Importantly, rapid administration of intranasal rescue medications has been associated with shorter durations of seizure activity as compared with rectal/intravenous routes. Intranasal rescue medications are also easy to use and socially acceptable. These factors potentially remove or reduce barriers to use and optimize the management of seizure clusters.

Danazol increases the oral bioavailability of midazolam by inactivation of hepatic and intestinal CYP3A in rats

Danazol (DNZ) is a synthetic androgen derivative used for the treatment of intractable hematological disorders. In this study, we investigated the effects of DNZ on CYP3A activity in hepatic and small intestinal microsomes and the pharmacokinetics of midazolam (MDZ), a typical substrate for CYP3A, in rats.MDZ 4-hydroxylation activities in hepatic and small intestinal microsomes significantly decreased 24 h after DNZ (100 mg/kg, i.p.) treatment. Time-dependent inactivation of MDZ 4-hydroxylation activities was noted when microsomes were pre-incubated with DNZ in the presence of a NADPH-generating system.The Western blot analysis indicated that the decrease observed in enzyme activity was not due to changes in the protein expression of CYP3A.In contrast to the intravenous administration, serum MDZ concentrations in DNZ-treated rats were markedly higher than those in control rats when administered orally. DNZ treatment increased MDZ oral bioavailability by approximately 2.5-folds.We herein demonstrated that DNZ increased the bioavailability of orally administered MDZ through irreversible inactivation of hepatic and intestinal CYP3A in rats.

Dose-dependent pharmacokinetics of midazolam in rats: influence of hepatic first-pass metabolism

1. To characterize the dose-dependent pharmacokinetics of midazolam and evaluate the intestinal and hepatic first-pass effects on midazolam in Sprague-Dawley rats, the concentrations and area under the concentration-time curve (AUC) of midazolam in the portal and systemic plasma were simultaneously determined with a double cannulation method.2. It was found that about 75% of the dose was left in the portal blood with different oral administration doses, while the bioavailability in the liver was 37.86% at 20 mg/kg, significantly higher than 9.16% at 2 mg/kg.3. The disproportional increase in AUC of midazolam and significant decrease in exposure of metabolites were observed in systemic plasma after hepatic portal vein administration. And in the in vitro study, the formation rate of the metabolites of midazolam significantly decreased when midazolam was at 300 μM compared with 100 μM.4. These results indicated that not only the saturation of first-pass metabolism but also the inhibition of hepatic metabolism is responsible for the nonlinear PK of midazolam. Thus, a rational dose should be chosen when midazolam is used as a probe in the drug-drug interaction study, particularly for orally administered drugs that undergo hepatic first-pass metabolism.

Delayed tezampanel and caramiphen treatment but not midazolam protects against long-term neuropathology after soman exposure

Prolonged status epilepticus (SE) can cause brain damage; therefore, treatment must be administered promptly after seizure onset to limit SE duration and prevent neuropathology. Timely treatment of SE is not always feasible; this would be particularly true in a mass exposure to an SE-inducing agent such as a nerve agent. Therefore, the availability of anticonvulsant treatments that have neuroprotective efficacy even if administered with a delay after SE onset is an imperative. Here, we compared the long-term neuropathology resulting from acutely exposing 21-day-old male and female rats to the nerve agent soman, and treating them with midazolam (3 mg/kg) or co-administration of tezampanel (10 mg/kg) and caramiphen (50 mg/kg), at 1 h postexposure (~50 min after SE onset). Midazolam-treated rats had significant neuronal degeneration in limbic structures, mainly at one month postexposure, followed by neuronal loss in the basolateral amygdala and the CA1 hippocampal area. Neuronal loss resulted in significant amygdala and hippocampal atrophy, deteriorating from one to six months postexposure. Rats treated with tezampanel-caramiphen had no evidence of neuropathology, except for neuronal loss in the basolateral amygdala at the six-month timepoint. Anxiety was increased only in the midazolam-treated rats, at one, three, and six months postexposure. Spontaneous recurrent seizures appeared only in midazolam-treated rats, at three and six months postexposure in males and only at six months in females. These findings suggest that delayed treatment of nerve agent-induced SE with midazolam may result in long-lasting or permanent brain damage, while antiglutamatergic anticonvulsant treatment consisting of tezampanel and caramiphen may provide full neuroprotection.

A Comparative Study on Effectiveness of Parental Presence versus Sedative Premedication for Reducing Anxiety in Children Undergoing General Anesthesia

Background

Preoperative anxiety is an important, yet often unattended problem in children. Minimizing anxiety and distress at the time of anesthetic induction may reduce adverse psychological and physiological outcomes. Sedative premedication and parental presence during anesthesia induction are among the most commonly employed strategies for reducing child anxiety.

Aims and Objective

The study aimed to compare the effectiveness of a pharmacological intervention (premedication with midazolam) versus behavioral intervention (parental presence) in reducing preoperative anxiety in children undergoing general anesthesia.

Methodology

Sixty patients of age group of 4-12 years, of ASA Grade 1 and 2 and either sex posted for elective surgery under general anesthesia were divided into two groups of 30 each Group M (midazolam group) and Group P (parental presence). Group M received intravenous midazolam 0.03-0.05 mg/kg preoperatively and anxiety was measured in preoperative room, during separation from parents and during introduction of anesthesia mask, whereas in Group P, parents accompanied the child inside the operation theater and anxiety was measured at preoperative room and during introduction of mask. Parental anxiety was measured in both groups at preoperative room and waiting room. Modified Yale Preoperative Anxiety Scale (mYPAS) and State Trait Anxiety Inventory (STAI) tool was used to measure anxiety in children and parents, respectively.

Results

The mean mYPAS score while the introduction of anesthesia mask in Group M was 31.30 ± 12.04 and in Group P was 63.19 ± 25.31, and the difference was found to be statistically significant (P = 0.001). In preoperative room, there was no significant difference in anxiety in the two study groups. The mean STAI score in Group P was 45.63 ± 1.45 and in Group M was 41.10 ± 1.69, and the difference was found to be statistically significant (P = 0.001). In preoperative room, parental anxiety was found to be comparable among the two groups. The mean duration of induction of anesthesia in Group M was 5.53 ± 1.01 min, and in Group P, it was 8.77 ± 2.03 min. The difference was found to be statistically significant (P = 0.001).

Conclusion

Both interventions were effective in reducing anxiety in children, but midazolam was more effective compared to parental presence. Parents in Group M were less anxious in the waiting room than Group P. Children in Group M were more compliant during the induction of anesthesia, hence a lesser duration of induction than Group P.

Economic benefits of remimazolam compared to midazolam and propofol for procedural sedation in colonoscopies and bronchoscopies

BACKGROUND

Sedation is common practice in endoscopic procedures to suppress a patient's level of consciousness while maintaining the cardio-respiratory function. Midazolam and propofol are the sedatives most frequently used for procedural sedation at the hospitals in Scandinavia. Remimazolam is a new ultra-short-acting benzodiazepine sedative and the present analysis aimed at estimating the economic benefits of introducing remimazolam for procedural sedation in colonoscopies and bronchoscopies in hospitals in Scandinavia.

METHOD

We developed a cost model applying a micro-costing approach that comprised the cost components that are affected by differences in the efficacy of remimazolam, midazolam and propofol, and the model estimated the cost per successful colonoscopy and bronchoscopy when using remimazolam, midazolam or propofol as sedation. A micro-costing approach was applied, and the model consisted of six stages representing the journey for patients undergoing endoscopies and was informed primarily by data from clinical studies on remimazolam.

RESULTS

We found a total cost of DKK 1,200 per successful colonoscopy procedure when using remimazolam, a total cost of DKK 1,320 when using midazolam and a total cost of DKK 1,255 when using propofol. Hence, the incremental saving per successful colonoscopy procedure of using remimazolam was estimated to be DKK 120 compared to midazolam and DKK 55 compared to propofol. The total cost per successful bronchoscopy procedure when using remimazolam was DKK 1,353 and DKK 1,724 for midazolam, resulting in an incremental saving per bronchoscopy of DKK 372 when using remimazolam. Performed sensitivity analyses identified the time in recovery as the largest contributor to uncertainty in the analyses of remimazolam compared to midazolam in colonoscopies and bronchoscopies. In the comparison of remimazolam and propofol in colonoscopies, procedure time was the largest contributor to uncertainty.

CONCLUSION

We found that procedural sedation with remimazolam was associated with economically meaningful savings compared to procedural sedation with midazolam and propofol in colonoscopies and to midazolam in bronchoscopies.

Time course of CYP3A activity during and after metamizole (dipyrone) in healthy volunteers

BACKGROUND AND PURPOSE

In patients of all ages, metamizole is a frequently used analgesic. Recently, metamizole has been identified as an inducer of, among others, cytochrome P450 (CYP) 3A activity, but the time course of this interaction has not been evaluated.

EXPERIMENTAL APPROACH

Using repeated oral microdoses (30 μg) of the CYP3A index substrate midazolam, we assessed changes in midazolam pharmacokinetics (area under the concentration-time curve from 2-4 h: AUC_2-4 and estimated partial metabolic clearance: eCl_met ) before, at steady-state, and after discontinuation of 3 x 1000 mg metamizole/d orally for 8 d.

KEY RESULTS

Significant changes in pharmacokinetic parameters were detected already three days after start of metamizole treatment. At the steady-state of enzyme induction, the geometric mean ratio of midazolam AUC_2-4 was substantially reduced to 0.18 (90 % confidence interval: 0.14-0.24) with a corresponding 5.43-fold (4.15-7.10) increase of eCl_met . After discontinuation of metamizole, the changes slowly recovered, but were still significant at the end of the observation period on the fifth day after discontinuation of metamizole therapy (AUC_2-4 reduced to 0.50 (0.41-0.63) and eCl_met 1.99-fold increased (1.60-2.47, p < 0.05)).

CONCLUSION AND IMPLICATIONS

Metamizole acts as a strong inducer of CYP3A already few days after start of metamizole administration and, thus, should be avoided in patients using drugs with narrow therapeutic index and major clearance via CYP3A. If their administration is essential, close monitoring and dose adjustment of co-medication should be performed as early as the first week after the initiation and after discontinuation of metamizole therapy.

Effectiveness of Nitrous Oxide versus Pethidine/Midazolam for Pain Relief in Minor Gynecological Operative Procedures: A Randomized Controlled Trial

Aim and Objective: To compare the analgesic effectiveness of the patient-controlled inhaled nitrous oxide (Entonox^®) with intravenous opioids (pethidine/midazolam) in reducing pain during minor gynecological operative procedures, including manual vacuum aspiration (MVA), fractional curettage and dilatation and curettage. Materials and Methods: Patients undergoing minor gynecological procedures from August 2021 to December 2022 were randomized to receive nitrous oxide or intravenous pethidine (50-75 micrograms) plus midazolam (2 mg). Pain scores during and post-procedure, satisfaction level, and side effects were assessed and compared. Results: A total of 106 patients met the inclusion criteria, including 53 in the pethidine/midazolam group and 53 in the nitrous oxide group. Baseline characteristics were comparable (p-value > 0.05). Pain scores during, immediately and 30 min after procedures were not significantly different in two groups (4.94 ± 3.15, 2.74 ± 2.57, 1.58 ± 2.13 vs. 5.47 ± 2.80, 2.98 ± 2.70, 1.64 ± 2.70; p-value: 0.174, 0.634, 0.889, for pethidine/midazolam vs. nitrous oxide group, respectively. Satisfaction scores were comparable in both groups (p-value > 0.05). However, the rate of side effects was significantly lower in the nitrous oxide group (3.8% vs. 28.3%; p-value 0.001). Additionally, the discharge scores showed a significantly faster recovery time in the nitrous oxide group at 60 and 90 min after the procedure; median (IQR): 10 (9-10) vs. 9 (8-10) and 10 (10-10) vs. 10 (8.5-10); p-value 0.002 and 0.029, respectively). Conclusions: Nitrous oxide is as effective as pethidine/midazolam for pain relief in minor gynecological operative procedures but associated with significantly lower side effects and significantly faster recovery time.

Tolerability and pharmacokinetics of intravenous allopregnanolone with and without midazolam pretreatment in two healthy dogs

The neurosteroid allopregnanolone (ALLO) is under investigation as a treatment for benzodiazepine-refractory status epilepticus (SE). Here we assess the cardiopulmonary safety of intravenous ALLO by itself and after a clinically recommended dose of midazolam (MDZ) in two healthy adult beagles. Each dog received ALLO (1 mg/kg, IV), and after a washout period of 2 weeks, the dog was dosed with MDZ (0.2 mg/kg, IV) followed 10 min later by ALLO. Behavioral state, vital signs, arterial blood gasses, blood chemistries, and plasma ALLO concentrations were monitored for up to 6 h after dosing. The dogs appeared sleepy but were fully responsive after both treatments. No depression of mean arterial pressure or respiratory rate was noted. Blood gas measurements failed to show evidence of drug-induced acute respiratory acidosis. Estimated maximum plasma ALLO concentrations were in the range of 1500 to 3000 ng/mL. The results indicate that intravenous ALLO can be used safely to treat benzodiazepine-refractory SE, even when administered shortly after a benzodiazepine.

Anesthetic effects of isoflurane and fentanyl infusion in capuchin monkeys (Sapajus sp) undergoing salpingectomy or deferentectomy, previously chemically restrained with ketamine-midazolam or ketamine-dexmedetomidine

BACKGROUND

This study evaluated the anesthetic and cardiorespiratory effects of two anesthetic protocols for salpingectomy or deferentectomy in capuchin monkeys (Sapajus sp).

MATERIALS AND METHODS

Five capuchin monkeys (5 per group) received ketamine (20 mg/kg) combined with midazolam (0.5 mg/kg; group KM) or dexmedetomidine (5 μg/kg; group KD) intramuscularly. Anesthesia is induced with propofol intravenously and maintained with isoflurane. Before the start of surgery, fentanyl 3 μg/kg was administered IV, and continuous infusion (10 μg/kg/min) IV was started. Times and quality of anesthetic recovery were evaluated postoperatively.

RESULTS

KM and KD resulted in adequate chemical restraint. KD resulted in bradycardia. Intraoperative heart rate and systolic blood pressure were higher in KM than in KD. Both groups had smooth recovery. Time to standing was longer in KM than in KD.

CONCLUSION

Both protocols allowed the performance of surgeries, with few cardiorespiratory effects. Anesthetic recovery was smooth and shorter in KD group.

Individual differences in the effects of midazolam on anxiety-like behavior, learning, reward, and choice behavior in male mice

Introduction

The aim of the present study was to investigate the behavioral effects of the benzodiazepine midazolam in male mice, in models of anxiolysis, learning, and abuse-related effects.

Methods

In a first set of experiments, male Swiss mice were submitted to the training session of a discriminative avoidance (DA) task on the elevated plus maze to evaluate anxiety-like behavior and learning after vehicle or midazolam (1, 2 or 5 mg/kg, i.g.) administration. The same animals were submitted to a conditioned place preference (CPP) protocol with midazolam (1, 2 or 5 mg/kg, i.g.). In a second experiment, outbred (Swiss) and inbred (C57BL/6) male mice were submitted to a two-bottle choice (TBC) oral midazolam drinking procedure. Animals were exposed to one sucrose bottle and one midazolam (0.008, 0.016 or 0.032 mg/ml) plus sucrose bottle.

Results

Midazolam (1 and 2 mg/kg) induced anxiolytic-like effects, and all doses of midazolam prevented animals from learning to avoid the aversive closed arm during the DA training session. Assessment of midazolam reward via the CPP procedure and choice via the TBC procedure showed notable variability. A 2-step cluster analysis for the CPP data showed that midazolam data were well-fitted to 2 separate clusters (preference vs. aversion), albeit with the majority of mice showing preference (75%). Correlational and regression analyses showed no relationship between midazolam reward and anxiolytic-like effects (time spent in the open arms in the DA test) or learning/memory. Two-step cluster analysis of the TBC data also demonstrated that, regardless of strain, mice overall fell into two clusters identified as midazolam-preferring or midazolam-avoiding groups. Both midazolam preference and avoidance were concentration-dependent in a subset of mice.

Discussion

Our findings show that midazolam preference is a multifactorial behavior, and is not dependent solely on the emergence of therapeutic (anxiolytic-like) effects, learning impairments, or on genetic factors (inbred vs. outbred animals).

Effect of capmatinib on the pharmacokinetics of substrates of CYP3A (midazolam) and CYP1A2 (caffeine) in patients with MET-dysregulated solid tumours

BACKGROUND

Preclinical studies showed that capmatinib reversibly inhibits cytochrome P450 (CYP) 3A4 and CYP1A2 in a time-dependent manner. In this study, we evaluated the effect of capmatinib on the exposure of sensitive substrates of CYP3A (midazolam) and CYP1A2 (caffeine) in patients with mesenchymal-epithelial transition (MET)-dysregulated solid tumours. Besides pharmacokinetics, we assessed treatment response and safety.

METHODS

This open-label, multicentre, single-sequence study consisted of a molecular prescreening period, a screening/baseline period of ≤28 days and a drug-drug interaction (DDI) phase of 12 days. On day 1 of the DDI phase, 37 patients received a single oral dose of midazolam 2.5 mg and caffeine 100 mg as a two-drug cocktail. Capmatinib 400 mg bid was administered from day 4 on a continuous dosing schedule. On day 9 of the DDI phase, patients were re-exposed to midazolam and caffeine. After the DDI phase, patients received capmatinib on continuous 21-day cycles until disease progression at the discretion of the investigator.

RESULTS

A 22% (90% confidence interval [CI] 7-38%) increase in the midazolam maximum plasma concentration (C_max ) was noted when administered with capmatinib, but this was deemed not clinically meaningful. Co-administration with capmatinib resulted in 134% (90% CI 108-163%) and 122% (90% CI 95-153%) increases in the caffeine area under the plasma concentration-time curve from time zero to infinity (AUC_inf ) and area under the plasma concentration-time curve from time zero to the last measurable point (AUC_last ), respectively, with no change in C_max . Adverse events were consistent with the known capmatinib safety profile. No new safety signals were reported in this study.

CONCLUSION

The data from this study demonstrated that capmatinib is a moderate CYP1A2 inhibitor. Capmatinib administration did not cause any clinically relevant changes in midazolam exposure.

Deep continuous patient-requested sedation until death: a multicentric study

OBJECTIVES

In 2016, a new law was adopted in France granting patients the right, under specific conditions, to continuous deep sedation until death (CDSUD). The goal of this study was to measure the frequency of requests for CDSUD from patients in palliative care.

METHODS

The data collected from the medical records of patients in palliative care units (PCU) or followed by palliative care support teams (PCST) in the Rhône-Alpes area, who died after CDSUD, focused on the patient's characteristics, the drugs used (and compliance with regulatory processes).

RESULTS

All 12 PCU and 12 of the 24 PCST were included. Among the 8500 patients followed, 42 (0.5%) requested CDSUD until death. The patients were: 65.7 (SD=13.7) years old, highly educated (69%), had cancer (81%), refractory symptoms (98%) and mostly psychoexistential distress (69%). The request was rejected for 2 (5%) patients and delayed for 31 (74%) patients. After a delay of a mean 8 days, 13 (31%) patients were granted CDSUD. The drug used was midazolam at 115 mg/24 hours (15-480), during a mean of 3 days. PCUs used lower dosages than PCSTs (83 vs 147), with significantly lower initial doses (39 mg vs 132 mg, p=0.01). A life-threatening condition was recorded in 13 cases (31%) and a collegial decision was taken in 25 cases (60%).

CONCLUSION

This study highlights the low rate of request and the even lower rate of CDSUD in specialised palliative care. However, the sedation for psychoexistential distress and the lack of procedure records raise ethical questions.

Exploring a case of incompatibility in a complex regimen containing Plasma-Lyte 148 in the pediatric intensive care

BACKGROUND

In the local pediatric intensive care unit, precipitation was observed in the intravenous catheter upon co-administration of four drugs together with the buffered electrolyte solution (Plasma-Lyte 148, Baxter). Co-infusion of incompatible combinations represents a safety concern.

AIMS

To reproduce the clinical case of precipitation. To further explore and understand the risk of precipitation, different combinations of the components as well as the corresponding electrolyte solution with 5% glucose (Plasma-Lyte 148 with 5% glucose) should be investigated.

METHODS

Physical compatibility of fentanyl, ketamine, midazolam, and potassium chloride was tested in combination with the buffered electrolyte solutions. The concentrations and infusion rates representative of children 10-40 kg were used to estimate mixing ratios. Analyses detecting visual particles (Tyndall beam) and sub-visual particles (light obscuration technology) were undertaken. Measured turbidity and pH in mixed samples were compared with unmixed controls.

RESULTS

Both midazolam and ketamine showed formation of visual and sub-visual particles upon mixing with Plasma-Lyte 148, respectively. Particle formation was confirmed by increased turbidity and a distinct Tyndall effect. pH in mixed samples mirrored the pH of the buffered electrolyte, suggesting that the solubility limits of midazolam, and in some ratios also ketamine, were exceeded. Midazolam also precipitated in combination with the glucose-containing product that held a lower pH, more favorable for keeping midazolam dissolved.

CONCLUSIONS

Replication of the case revealed that both midazolam and ketamine contributed to the precipitation. Midazolam and ketamine were both evaluated as incompatible with the buffered electrolyte solution and midazolam also with the buffered electrolyte-glucose solution and should not be co-administered in the same i.v.-catheter line. Fentanyl and potassium chloride were interpreted as compatible with both buffered electrolytes.

Comparison of sedation using propofol versus midazolam in patients admitted to the intensive care unit after extracorporeal cardiopulmonary resuscitation for out-of-hospital cardiac arrest: a multicentre observational study

BACKGROUND

Optimal sedation regimens for patients after extracorporeal cardiopulmonary resuscitation (ECPR) remain unclear. This study compared the outcomes of patients who received propofol and midazolam for sedation post-ECPR for out-of-hospital cardiac arrest (OHCA).

METHODS

A retrospective cohort study analysed data from the Study of Advanced life support for Ventricular fibrillation with Extracorporeal circulation in Japan, including patients admitted to 36 intensive care units (ICU) in Japan post-ECPR for OHCA of cardiac aetiology between 2013 and 2018. One-to-one propensity score-matched analysis compared outcomes between patients post-ECPR for OHCA who received exclusive treatment with a continuous propofol infusion (propofol users) and those who received exclusive treatment with a continuous midazolam infusion (midazolam users). The cumulative incidence and competing risk methodology were used to compare the time to liberation from mechanical ventilation and ICU discharge.

RESULTS

Propensity score-matching created 109 matched pairs of propofol and midazolam users with balanced baseline characteristics. Competing risk analysis for the 30-day ICU period showed no significant difference in the probability of liberation from mechanical ventilation (0.431 vs. 0.422, P = 0.882) and ICU discharge (0.477 vs. 0.440, P = 0.634). Furthermore, there was no significant difference in the proportion of 30-day survival (0.399 vs. 0.398, P = 0.999), 30-day favourable neurological outcome (0.176 vs. 0.185, P = 0.999), and vasopressor requirement within 24-h post-ICU admission (0.651 vs. 0.670, P = 0.784).

CONCLUSIONS

This multicentre cohort study revealed no significant differences in mechanical ventilation duration, ICU stay length, survival, neurological outcomes, and vasopressor requirement between propofol and midazolam users admitted to the ICU after ECPR for OHCA.

Effect of midazolam in autism spectrum disorder: A retrospective observational analysis

BACKGROUND

While midazolam is commonly used as premedication for uncooperative patients, its effects are difficult to predict in patients with autism spectrum disorder for whom abnormalities in gamma-aminobutyric acid have been reported. This study aimed to investigate the influence of autism spectrum disorder on the effect of midazolam when used as premedication.

METHODS

This retrospective observational study was performed between April 2017 and August 2018. Before inducing general anesthesia with sevoflurane for dental treatment, 390 uncooperative patients received premedication with midazolam. Ordinal logistic regression analysis was performed with the Observer's Assessment of Alertness/Sedation score 30 min after premedication as the objective variable. Age, sex, American Society of Anesthesiologists physical status class, premedication route, dose per body weight, presence of specific disorders (autism spectrum disorder, intellectual disability, epilepsy, cerebral palsy, and other psychiatric disorders), and regular benzodiazepine or non-benzodiazepine psychotropic administration were included as explanatory variables. Kendall's rank correlation coefficient was used to assess the correlation between the Observer's Assessment of Alertness/Sedation score and cooperation level (1, obvious negative response; 2, negative response; 3, positive reaction; 4, obvious positive reaction) during admission and inhalation induction. All data were extracted from anesthesia and medical records.

RESULTS

Age (odds ratio 1.437 [95% confidence interval (CI) 1.213-1.708], P < .001), autism spectrum disorder (1.318 [1.079-1.612], P = .007), benzodiazepine medication (0.574 [0.396-0.827], P = .002), and intramuscular route (1.478 [1.137-1.924], P = .004) were significantly associated with the Observer's Assessment of Alertness/Sedation score, while the score was negatively associated with cooperation levels during admission (τ = -0.714, P < .001) and inhalation induction (τ = -0.606, P < .001).

CONCLUSIONS

Patients with autism spectrum disorder may be susceptible to premedication with midazolam; however, regular benzodiazepine administration may reduce the effect.

Efficacy of median nerve hydrodissection by hyalase versus midazolam in the treatment of carpal tunnel syndrome

Background: The objective was to determine which of midazolam or hyalase could improve the pain score and functional disability in median nerve hydrodissection. Methods: In a double-blind study with two groups, both received bupivacaine 15 mg with either 300 IU hyalase in 2 ml of saline (group HA) or 2 mg of midazolam in 2 ml of sterile saline (group MZ). Results: Statistically significantly lower post-injection Visual Analog Scale scores in group MZ compared with group HA at all follow-ups. Group MZ had significantly lower functional disability scores than group HA. Conclusion: Both drugs yielded favorable results. Midazolam was more impactful in alleviating pain and reducing functional disability up to 6 months.

Comparison of dexmedetomidine alone or with other sedatives for paediatric sedation during magnetic resonance imaging: a systematic review

Aim To compare the outcome of sole dexmedetomidine or with other sedative drugs in paediatric patients during magnetic resonance imaging (MRI). Methods Literature was obtained from PubMed and ScienceDirect from 2010-2020 using key words: sedation, paediatric, dexmedetomidine, ambulatory, MRI, ketamine, propofol, midazolam. The literature selection was based on Participant, Intervention, Comparators, Outcomes (PICO) analysis. All English full-text and peer-reviewed articles were included. The primary outcome was hemodynamic stability, respiratory compromise, and recovery time. The risk of bias analysis was assessed using Cochrane collaboration Risk of Bias (RoB 2.0). Result Of 106 studies, 17 studies were included with a total 3.430 paediatric patients undergoing MRI. Dexmedetomidine alone provides a more stable hemodynamic but longer recovery time than ketamine, propofol or midazolam. The combination of dexmedetomidine and ketamine provides more stable hemodynamics, especially in the incidence of hypotension and bradycardia, and does not significantly reduce airway configuration more than sole dexmedetomidine or ketamine. Intranasal dexmedetomidine is more recommended than its combination with midazolam. Combining dexmedetomidine with ketamine, propofol or midazolam provides a shorter recovery time. Conclusion A combination of dexmedetomidine with other sedatives such as ketamine, propofol and midazolam is better than sole dexmedetomidine for paediatric sedation during magnetic resonance imaging.

Influence of Age and Sex on the Pharmacokinetics of Midazolam and the Depth of Sedation in Pediatric Patients Undergoing Minor Surgeries

Whether age and sex influence the depth of sedation and the pharmacokinetics of midazolam is currently unknown. The influence of age and sex was investigated in 117 children (2 to 17 years) who required intravenous sedation for minor surgery (0.05 mg/kg). Plasma concentrations and sedation effects were simultaneously measured. The measured concentrations were analyzed using a two-compartment model with first-order elimination. Among the age ranges, significant differences were found (p < 0.05) between the volume of distribution (Vd) of the first compartment (V1) and that of the second (V2). With respect to sex, differences in V2 were found between age groups. At the administered dose, in patients younger than 6 years, a profound sedative effect (40-60 BIS) was observed for up to 120 min, while in older children, the effect lasted only half as long. The differences found in the Vd and bispectral index (BIS) in patients younger than 6 years compared to older patients may be due to immature CYP3A activity and body fat content; furthermore, the Vd varies with age due to changes in body composition and protein binding. Patients younger than 6 years require intravenous (IV) doses <0.05 mg/kg of midazolam for deep sedation. Dosage adjustments according to age group are suggested.

Cardiorespiratory Response to Sedative Premedication in Preschool Children: A Randomized Controlled Trial Comparing Midazolam, Clonidine, and Dexmedetomidine

PURPOSE

Sedative premedication in children may negatively impact their cardiorespiratory status during the perioperative course, and no clear consensus exists on the optimal premedication treatment for pediatric patients. The objective was to compare the perioperative cardiorespiratory responses to sedation using three different sedative premedication regimens in preschool children scheduled for surgery with total intravenous anesthesia.

DESIGN

A single-center randomized controlled trial.

METHODS

This is a planned secondary analysis of a study conducted at a 200-bed tertiary referral hospital. Ninety children participated in the study. They were aged 2-6 years and scheduled for ear, nose, and throat surgery with propofol/remifentanil anesthesia. Participants were randomly assigned to receive oral midazolam 0.5 mg/kg^-1 (MID), oral clonidine 4 mcg/kg^-1 (CLO), or intranasal dexmedetomidine 2 mcg/kg^-1 (DEX). The main outcome measures were the sedation level, based on the Ramsay Sedation Scale (RSS), and cardiorespiratory status, monitored during the perioperative period.

FINDINGS

The final cohort had 83 children (MID, n=27; CLO, n=26; DEX, n=30), with similar intergroup patient characteristics. RSS scores were lower in the MID group than in the CLO and DEX groups before induction and within 30 min postsurgery (P<0.001 and P=0.006, respectively). A negative correlation existed between the RSS and heart rate (HR) (r=-0.570, P<0.001). Before anesthesia induction, the respiratory rate was lowest in the DEX group (MID 21.5±1.7 min^-1, CLO 20.6±2.6 min^-1, DEX 20.2±1.7 min^-1; P=0.042). The HR was lower in the CLO and DEX groups than in the MID group (MID, 102.8±10.0 min^-1; CLO, 87.4±9.6 min^-1; DEX, 87.6±7.9 min^-1; P<0.001). The HR was lower immediately after induction (P=0.009) and intraoperatively (P=0.025) in the CLO and DEX groups than in the MID group.

CONCLUSIONS

When used as premedication before propofol/remifentanil anesthesia, clonidine and dexmedetomidine provided deeper preoperative sedation compared to midazolam. From a clinical perspective, all three study drugs provided essentially stable cardiovascular and respiratory conditions during the entire perioperative period.