A dose escalation study in sheep of the effects of the benzodiazepine CNS 7056 on sedation, the EEG and the respiratory and cardiovascular systems

Efficacy of Single-Bolus Administration of Remimazolam During Induction of Anesthesia in Patients Undergoing Cardiac Surgery: A Prospective, Single-Center, Randomized Controlled Study

BACKGROUND

Remimazolam is a recently marketed ultrashort-acting benzodiazepine. This drug is considered safe and effective during general anesthesia; however, limited information is available about its effects on patients undergoing cardiac surgery. Therefore, the present study was conducted to evaluate the efficacy and hemodynamic stability of a bolus administration of remimazolam during anesthesia induction in patients undergoing cardiac surgery.

METHODS

Patients undergoing elective cardiac surgery were randomly assigned to any 1 of the following 3 groups: anesthesia induction with a continuous infusion of remimazolam 6 mg/kg/h (continuous group), a single-bolus injection of remimazolam 0.1 mg/kg (bolus 0.1 group), or a single-bolus injection of remimazolam 0.2 mg/kg (bolus 0.2 group). Time to loss of responsiveness, defined as modified Observer's Assessment of Alertness/Sedation Scale <3, and changes in hemodynamic status during anesthetic induction were measured.

RESULTS

Times to loss of responsiveness were 137 ± 20, 71 ± 35, and 48 ± 9 seconds in the continuous, bolus 0.1, and bolus 0.2 groups, respectively. The greatest mean difference was observed between the continuous and bolus 0.2 groups (89.0, 95% confidence interval [CI], 79.1-98.9), followed by the continuous and bolus 0.1 groups (65.8, 95% CI, 46.9-84.7), and lastly between the bolus 0.2 and bolus 0.1 groups (23.2, 95% CI, 6.6-39.8). No significant differences were found in terms of arterial blood pressures and heart rates of the patients.

CONCLUSIONS

A single-bolus injection of remimazolam provided efficient anesthetic induction in patients undergoing cardiac surgery. A 0.2 mg/kg bolus injection of remimazolam resulted in the shortest time to loss of responsiveness among the 3 groups, without significantly altering the hemodynamic parameters. Therefore, this dosing can be considered a favorable anesthetic induction method for patients undergoing cardiac surgery.

Comparison of Remimazolam and Propofol in Recovery of Elderly Outpatients Undergoing Gastrointestinal Endoscopy: A Randomized, Non-Inferiority Trial

Purpose

We designed this trial to compare the recovery time of remimazolam and propofol in elderly patients undergoing painless gastrointestinal endoscopy.

Patients and Methods

In this randomized, non-Inferiority trial, 360 patients aged 65 years or older, scheduled for elective outpatient gastrointestinal endoscopy, were randomly assigned to the remimazolam combined with fentanyl (RF) group or the propofol combined with fentanyl (PF) group. The primary outcome was the post-anesthesia care unit (PACU) stay time, defined as the time from the end of the examination to scoring 9 points using the Modified Post-Anesthetic Discharge Scoring System (MPADSS) criteria. Secondary outcomes included sedation-related adverse events, recall, injection pain, as well as postoperative Quality of Recovery-15 (QoR-15) scores and Pittsburgh Sleep Quality Index (PSQI) scores at 1 day, 1 week, and 1 month postoperatively.

Results

A total of 351 patients completed the study, with 174 receiving remimazolam and 177 receiving propofol. The PACU stay time in RF group was non-inferior to that in PF group [14 (11, 18) vs 13 (10, 17), mean difference 1 (95% confidence interval 0, 2), P=0.084 for noninferiority]. However, remimazolam was associated with lower rate of hypoxemia [4.7% (8/180) vs 12.4% (22/180), P=0.011], reduced use of vasoactive drugs [1 (0, 1) vs 1 (1, 2), P<0.001], less injection pain [2 (1.2%) vs 35 (21.3%), P<0.001], and lower recall [20 (11.8%) vs 36 (20.3%), P=0.034]. There were no differences in the QoR-15 scores and PSQI scores at postoperative 1 day, 1 week, and 1 month between groups.

Conclusion

This non-inferiority study revealed that in elderly outpatients undergoing gastrointestinal endoscopy, remimazolam achieved recovery times comparable to propofol, with fewer associated complications.

The Impact of Fentanyl on the Effective Dose of Remimazolam-Induced Sedation in Elderly Female Patients: An Up-and-Down Sequential Allocation Trial

Purpose

This study aimed to investigate the influence of fentanyl on the effective dose of remimazolam-induced sedation in elderly female patients undergoing general anesthesia.

Patients and Methods

Sixty female patients aged 65-80 years undergoing selective general anesthesia were randomized into two groups: Group R+F received an initial dose of remimazolam (7.5 mg) with fentanyl (1 μg/kg), while Group R received remimazolam alone. Dosing adjustments (±2.5 mg) were made based on the response of the preceding patient using the up-and-down allocation technique. The ED50 and ED95 were calculated using a sequential formula and probit regression. Probit regression was also used to assess the relative potency of remimazolam between groups. Sedation levels were evaluated using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale.

Results

The ED50 for remimazolam was significantly lower in Group R+F compared to Group R (p= 0.007). Probit regression estimated the ED50 and ED95 values for Group R+F at 4.878 mg (95% CI, 3.845-5.859) and 8.184 mg (95% CI, 6.636-13.546), respectively. In contrast, Group R demonstrated ED50 and ED95 values of 6.733 mg (95% CI, 5.533-8.068) and 11.298 mg (95% CI, 9.101-19.617), respectively.

Conclusion

This study provides compelling evidence that the administration of 1 μg/kg of fentanyl significantly reduces the required sedative dose of remimazolam by approximately 30% during induction in elderly patients. Importantly, the concomitant use of 1 μg/kg of fentanyl does not increase the risk of adverse effects such as hypotension, respiratory depression.

The effects of remimazolam combined with sufentanil on respiration, circulation and sedation level in patients undergoing colonoscopy

BACKGROUND

The main sedative which is propofol in painless gastroenteroscopy, has a high risk of reducing blood pressure and respiratory depression. Remimazolam (a short-acting benzodiazepine) is expected to be widely used in painless gastroenteroscopy due to its rapid onset, rapid metabolism and light respiratory and circulation inhibition.

METHODS

A randomized, single-blind, parallel, controlled study, 123 outpatients who were undergoing painless colonoscopy and ramdomly divided into group A, B and C, in Hangzhou First People's Hospital, July-December 2021. All patients were intravenously injected with 5 µg sufentanil for analgesic preconditioning. The group A was induced by 0.2 mg/kg remimazolam besylate. The group B was induced by 0.25 mg/kg remimazolam besylate. And the group C was inducted by 2.0 mg /kg propofol. If the patients had limb movement or MOAA/S score > 3 and so on, remimazolam besylate was added at 2.5 mg/ time in group A and B, and propofol emulsion injection was added at 0.5 mg/kg/ time in group C. During the operation, according to the actual situation, remimazolam was per added 2.5 mg in the experimental group, and propofol was 0.5 mg/kg in the control group. Heart rate (HR), non-invasive blood pressure (BP), respiratory rate (RR), pulse oxygen saturation (SpO2), and improved vigilance/sedation score (MOAA/S) of patients was recorded from entering endoscopy room to get out of the anesthesia recovery room, also including perioperative adverse events, other medications or treatments, the time of patients waking up and leaving the hospital.

RESULTS

The successful rate of induction in three groups was 100%. There was no significant difference in the sedation completion rate among the three groups (Group A:90.2%, Group B: 92.7%, Group C: 92.7%, P = 1.000). The rate of adverse events after administration: group A(27.0%) and B(36.8%) both lower than group C(71.0%),P < 0.001;There was no significant difference between group A and group B, P > 0.744;The average time from the last drug administration to meet the discharge criteria of the subjects in three groups was as follows: The average time of group A(16.2 min) and Group B(16.5 min) both shorter than group C(19.6 min), P = 0.001; There was no significant difference between group A and group B, P = 0.742.

CONCLUSIONS

This study revealed that remimazolam is a safe and effective medication for colonoscopy sedation, the security of remimazolam is better than propofol, and the sedative effect with the initial dose of 0.25 mg/kg of remimazolam is optimal.

TRIAL REGISTRATION

China Clinical Trial Center with registration number: 2100052615,02/11/2021.

Remimazolam for sedation in gastrointestinal endoscopy: A comprehensive review

Worldwide, a majority of routine endoscopic procedures are performed under some form of sedation to maximize patient comfort. Propofol, benzodiazepines and opioids continue to be widely used. However, in recent years, Remimazolam is gaining immense popularity for procedural sedation in gastrointestinal (GI) endoscopy. It is an ultra-short-acting benzodiazepine sedative which was approved by the Food and Drug Administration in July 2020 for use in procedural sedation. Remimazolam has shown a favorable pharmacokinetic and pharmacodynamic profile in terms of its non-specific metabolism by tissue esterase, volume of distribution, total body clearance, and negligible drug-drug interactions. It also has satisfactory efficacy and has achieved high rates of successful sedation in GI endoscopy. Furthermore, studies have demonstrated that the efficacy of Remimazolam is non-inferior to Propofol, which is currently a gold standard for procedural sedation in most parts of the world. However, the use of Propofol is associated with hemodynamic instability and respiratory depression. In contrast, Remimazolam has lower incidence of these adverse effects intra-procedurally and hence, may provide a safer alternative to Propofol in procedural sedation. In this comprehensive narrative review, highlight the pharmacologic characteristics, efficacy, and safety of Remimazolam for procedural sedation. We also discuss the potential of Remimazolam as a suitable alternative and how it can shape the future of procedural sedation in gastroenterology.

An ultra-short-acting benzodiazepine in thalamic nucleus reuniens undermines fear extinction via intermediation of hippocamposeptal circuits

Benzodiazepines, commonly used for anxiolytics, hinder conditioned fear extinction, and the underlying circuit mechanisms are unclear. Utilizing remimazolam, an ultra-short-acting benzodiazepine, here we reveal its impact on the thalamic nucleus reuniens (RE) and interconnected hippocamposeptal circuits during fear extinction. Systemic or RE-specific administration of remimazolam impedes fear extinction by reducing RE activation through A type GABA receptors. Remimazolam enhances long-range GABAergic inhibition from lateral septum (LS) to RE, underlying the compromised fear extinction. RE projects to ventral hippocampus (vHPC), which in turn sends projections characterized by feed-forward inhibition to the GABAergic neurons of the LS. This is coupled with long-range GABAergic projections from the LS to RE, collectively constituting an overall positive feedback circuit construct that promotes fear extinction. RE-specific remimazolam negates the facilitation of fear extinction by disrupting this circuit. Thus, remimazolam in RE disrupts fear extinction caused by hippocamposeptal intermediation, offering mechanistic insights for the dilemma of combining anxiolytics with extinction-based exposure therapy.

Validation of the anesthetic effect of a mixture of remimazolam, medetomidine, and butorphanol in three mouse strains

Proper administration of anesthesia is indispensable for the ethical treatment of lab animals in biomedical research. Therefore, selecting an effective anesthesia protocol is pivotal for the design and success of experiments. Hence, continuous development and refinement of anesthetic agents are imperative to improve research outcomes and elevate animal welfare. "Balanced anesthesia" involves using multiple drugs to optimize efficacy while minimizing side effects. The medetomidine, midazolam, and butorphanol, called MMB, and medetomidine, alfaxalone, and butorphanol, called MAB, are popular in Japan. However, the drawbacks of midazolam, including its extended recovery time, and the narrow safety margin of MAB, have prompted research for suitable alternatives. This study replaced midazolam in the MMB combination with remimazolam (RMZ), which is noted for its ultra-short half-life. The resulting combination, called MRB, was effective in providing a wider safety margin compared to MAB while maintaining an anesthesia depth equivalent level to that of MMB in mice. Notably, MRB consistently exhibited better recovery scores after antagonist administration in contrast to MMB. Furthermore, the re-sedation phenomenon observed with MMB was not observed with MRB. The rapid metabolism of RMZ enables reliable anesthesia induction, circumventing the complications linked to MAB. Overall, MRB excelled in providing extended surgical anesthesia and swift post-antagonist recovery. These results highlight the potential of RMZ for broader animal research applications.

Clinical Application and Research Progress of Remimazolam for Pediatric Patients

Remimazolam is a novel ultrashort-acting benzodiazepine that allosterically modulates γ-aminobutyric acid type A (GABAA) receptors to exert sedative effects. Remimazolam has the properties of controllable sedation, rapid onset, and a short duration of action, along with minor depression of circulation and respiration. Remimazolam has been approved for clinical use since 2020 in Japan, and it has been applied for procedural sedation, general anesthesia induction and maintenance, and sedation in ICU patients, and has been proven to be safe and effective. Currently, no consensus has been reached on the clinical application of remimazolam in pediatric patients. This review introduces the clinical research progress and limitations of remimazolam in recent years, aiming to supply scientific guidance and a theoretical reference for the application of remimazolam in pediatric anaesthesia.

Progress in the development of TRPV1 small-molecule antagonists: Novel Strategies for pain management

Transient receptor potential vanilloid 1 (TRPV1) channels are widely distributed in sensory nerve endings, the central nervous system, and other tissues, functioning as ion channel proteins responsive to thermal pain and chemical stimuli. In recent years, the TRPV1 receptor has garnered significant interest as a potential therapeutic approach for various pain-related disorders, particularly TRPV1 antagonists. The present review offers a comprehensive, systematic exploration of both first- and second-generation TRPV1 antagonists in the context of pain management. Antagonists are categorized and explicated according to their structural characteristics. Detailed examination of binding modes, structural features, and pharmacological activities, alongside a critical appraisal of the advantages and limitations inherent to typical compounds within each structural category, are undertaken. Detailed discussions of the binding modes, structural features, pharmacological activities, advantages, and limitations of typical compounds within each structural category offer valuable insights and guidance for the future research and development of safer, more effective, and more targeted TRPV1 antagonists.

Remimazolam and serious adverse events: A scoping review

Remimazolam is anticipated to be an interesting anaesthetic and sedative. It combines the pharmacodynamic properties of midazolam with pharmacokinetic properties similar to remifentanil. However, worrisome case reports of anaphylaxis, delayed emergence and re-sedation have emerged recently and necessitate further investigation.PubMed (including MEDLINE) and EMBASE were searched for all studies reporting serious adverse events where remimazolam was administered for sedation or anaesthesia.Thirty-six case reports and 73 trials were identified, involving a total of 6740 patients who received remimazolam. Hypotension was reported in 911 cases, delayed emergence in 68 cases, anaphylaxis in 10 cases and re-sedation in 8 cases. The incidence of hypotension seems to be lower compared with other anaesthetics, even in high-risk patients.Delayed emergence might be related to the metabolism of remimazolam through carboxylesterase 1 (CES1), a tissue esterase predominant in the liver. There is significant interindividual variation, and it is inhibited by flavonoids, fatty acids and alcohol. Individual benzodiazepine sensitivity has also been reported. A higher BMI, older age and low plasma albumin concentration are risk factors for delayed emergence. Anaphylaxis might be related to a non-IgE-mediated effect of the excipient dextran-40 or a partially IgE-mediated reaction to remimazolam itself. Resedation has been reported after flumazenil reversal and is explained by the specific pharmacokinetic properties of flumazenil and remimazolam. Reversal by flumazenil should be reserved for and used carefully in patients with delayed emergence.

VISUAL ABSTRACT

http://links.lww.com/EJA/A864 .

Determination of the 50% and 95% Effective Dose of Remimazolam Combined with Propofol for Intravenous Sedation During Day-Surgery Hysteroscopy

Purpose

Remimazolam has demonstrated the potential as a valuable medication for procedural sedation. However, there were some shortcomings for higher doses of remimazolam during hysteroscopy in spite of less frequent adverse events. The aim of this study was to find the 50% and 95% effective dose (ED₅₀ and ED₉₅) of remimazolam when combined with propofol for intravenous sedation during day-surgery hysteroscopy.

Patients and Methods

Patients were randomly assigned evenly (20 per group) to one of five different dosage of remimazolam: group A (0.05mg/kg), group B (0.075mg/kg), group C (0.1mg/kg), group D (0.125mg/kg) or group E (0.15mg/kg). Intravenous injection of sufentanil 0.1µg/kg was administered before sedative medication. Intravenous anesthesia was commenced with remimazolam. Subsequently, propofol was administered at 1mg/kg and maintained at 6mg/kg/h. Success was defined when the patient did not move during cervical dilation, had sufficient sedation as judged by SE <60 and no requirement for rescue doses. The success rate, induce and average dosage of propofol, the induction time, total surgery time, recovery time, and adverse events were recorded. Estimate of ED₅₀ and ED₉₅ with 95% confidence interval (CI) was performed by probit regression.

Results

The mean (95% CI) values for ED₅₀ and ED₉₅ of remimazolam in patients were 0.09 (0.08-0.11) mg/kg and 0.21 (0.16-0.35) mg/kg, respectively. There was no difference in the induction time, total surgery time, and recovery time among groups. No serious adverse events occurred in all patients.

Conclusion

The dose-response effects of remimazolam were evaluated for intravenous sedation during hysteroscopy. A combination of remimazolam and propofol was recommended to produce stabler sedation, reduce the total dosage and have less effect on cardiovascular and respiratory depression.

Efficacy and safety of remimazolam tosylate for sedation during upper gastrointestinal endoscopy: study protocol for a multicenter randomized controlled trial

BACKGROUND

Gastrointestinal endoscopy has been associated with difficult experiences and can leave patients with an unpleasant impression. Propofol and midazolam are the most commonly used intravenous anesthetics for sedation during gastrointestinal endoscopy. However, cardiac and pulmonary adverse events are the primary concerns associated with the use of these sedatives. Remimazolam tosylate is an ultra-short-acting benzodiazepine drug with a mild inhibitory effect on the respiratory and circulatory systems. These properties qualify remimazolam tosylate to be used as a replacement for propofol or midazolam as a sedative during gastrointestinal endoscopy. This study aims to describe the efficacy and safety of remimazolam tosylate as a sedative for upper gastrointestinal endoscopy.

METHODS

A multicenter, randomized, single-blind, parallel-controlled, noninferiority clinical study will be conducted to evaluate the efficacy and safety of remimazolam tosylate as a sedative during upper gastrointestinal endoscopy. Participants (n = 1800) will be randomized to receive remimazolam tosylate at 0.15 mg/kg (experimental group 1), remimazolam tosylate at 0.2 mg/kg (experimental group 2), or propofol at 1.5 mg/kg (control group). Procedure success will be assessed and defined as the completion of upper gastrointestinal endoscopy without the administration of a rescue sedative agent or more than two top-up doses of the trial drug in any 5-min period after initial administration. Sedation quality will be evaluated using the Modified Observer's Assessment of Alertness/Sedation score. Adverse events will be recorded to evaluate safety.

DISCUSSION

This study will determine the optimal dosage of remimazolam tosylate during upper gastrointestinal endoscopy and will describe its efficacy and safety. These findings may contribute to a more comfortable and safer experience for patients compared with that when the conventional sedative propofol is used.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04727034. Registered on February 18, 2021.

Efficacy and safety of different doses of remimazolam tosylate for colonoscopy: single-center, prospective, randomized, double-blind, parallel trial

Background

Remimazolam tosylate is a new sedative combining the advantages of etomidate with remifentanil. Remimazolam tosylate shows effective in colonoscopy, but the optimal dose is not confirm. In this study, a single-center, prospective, randomized, double-blind, parallel trial were performed to compare the efficacy and safety of different doses of remimazolam tosylate for colonoscopy.

Methods

Before colonoscopy, 120 recruited patients were randomized with a 1:1:1 ratio into 3 treatment groups: group A, 0.1 mg/kg remimazolam tosylate; group B, 0.15 mg/kg remimazolam tosylate; group C, 0.2 mg/kg remimazolam tosylate. Patients received 1 µg/kg fentanyl by intravenous injection over 30 s followed by the respective induction dose of remimazolam tosylate over 1 min (±5 s). When adequate sedation was achieved, colonoscopy was performed. Sedation was maintained at Modified Observer's Assessment of Alertness/Sedation (MOAA/S) ≤4 during the procedure. The additional administration of remimazolam tosylate (0.05 mg/kg per time) was permitted when necessary.

Results

Forty-one patients, 39 patients and 40 patients were respectively analyzed in group A, group B and group C. The procedural success rate was 80.49%, 87.18% and 95.00% in group A, group B and group C, respectively. During the induction period, patients in group A required additional doses of remimazolam tosylate more frequently than in group B and group C, but less during the maintenance period (all P<0.05). There was no significant difference in the induction time or time to recovery among the three groups. Incidence of adverse events (such as hypotension, hyoxemia and bucking) was similar among the three groups.

Conclusions

The initial loading doses of 0.1, 0.15, and 0.2 mg/kg remimazolam tosylate were all efficacy and safety for patients undergoing colonoscopy, and fewer times of the drug was re-administered.

Trial Registration

Chinese Clinical Trial Registry ChiCTR2000041331.

Anesthetic Management Using Remimazolam for Transcatheter Edge-to-Edge Repair of the Mitral Valve in Patients With Reduced Ejection Fraction: A Case Report of Two Cases

Remimazolam is an ultrashort-acting benzodiazepine that causes minimal hemodynamic changes. We present two patients, with reduced ejection fraction, who underwent remimazolam anesthesia for transcatheter edge-to-edge repair of the mitral valve with the MitraClip system. In case 1, the patient’s vitals were stable throughout the surgery. However, in case 2, which had a lower cardiac output, the patient’s blood pressure decreased remarkably after anesthesia induction. Though remimazolam does not alter the cardiac output, it reportedly has vasodilatory effects. Since remimazolam can reduce blood pressure in patients where the reduction in cardiac output is compensated for by high peripheral vascular resistance, caution should be exercised.

Profile of Remimazolam in Anesthesiology: A Narrative Review of Clinical Research Progress

Remimazolam is a novel short-acting γ-aminobutyric acid (GABA) receptor agonist with typical characteristics of benzodiazepine sedative drugs, nonorgan-dependent metabolism, long-term infusion without accumulation, and no injection pain. It is quite different from the other current sedative drugs and has broad prospects for application. It has been established that the metabolites of remimazolam are inactive, and the interactions with other drugs are weak with slight cardiopulmonary suppressive effects, showing good effectiveness and safety. During the 2-year period that it has been on the market, remimazolam has been used in multiple clinical scenarios, such as the induction and maintenance of general anesthesia and sedation in outpatient minor procedures or examinations. However, it's use has also prompted widespread concern around the world. Therefore, given its short- and rapid-acting, controllable characteristics remimazolam deserves in-depth study in order for it to be used in fast-track surgery, comfort diagnosis and treatment. Notably, such agents might be of great significance, especially in elderly individuals, patients with critical diseases or patients with liver and kidney insufficiency. The current study reviews recent clinical studies (2015-2022) on remimazolam and summarizes the characteristics of its applications. Specifically, the use of remimazolam in some specific populations are described. This study attempts to provide scientific support for the clinical application of this novel sedative drug in the field of anesthesia.

Remimazolam alleviates neuropathic pain via regulating bradykinin receptor B1 and autophagy

OBJECTIVES

Neuropathic pain (NP) represents a broad scope of various pathological ramifications of the nervous system. Remimazolam is a proved sedative in treating neuropathic pain. Considering the Bradykinin receptor's vital role and the potentials of Bradykinin receptor B1 (BDKRB1) in the neuropathic pain-signalling pathway, we nominated them as a primary target for remimazolam.

METHODS

In this study, rats were injected with complete freund's adjuvant (CFA) to construct NP models in vivo. BV2 microglia cells were treated with LPS to establish NP model in vitro. qRT-PCR, ELISA, western blot and immunofluorescence were applied to determine gene expression.

KEY FINDINGS

Our findings revealed that BDKRB1 was overexpressed in NP models in vivo, while R715 (an antagonist of BDKRB1) suppressed the levels of BDKRB1 and inhibited the hyperpathia induced by spinal nerve litigation surgery. Moreover, remimazolam inactivated BDKRB1 signalling via suppressing NF-κB translocation and decreased the release of pro-inflammatory cytokines. Additionally, remimazolam suppressed the translocation of NF-κB, and inhibited autophagic lysosome formation in vivo and in vitro. However, R838 (an agonist of BDKRB1) reversed the effects of remimazolam.

CONCLUSIONS

Remimazolam downregulated BDKRB1, inhibited BDKRB1/RAS/MEK signalling pathway and regulated the autophagic lysosome induction, exhibiting a better outcome in the NP.

Anaesthetic management using remimazolam in a patient with severe aortic stenosis: a case report

Background

The administration of general anaesthesia in patients with aortic stenosis (AS) requires careful attention to haemodynamics. We used remimazolam for the induction and maintenance of anaesthesia in a woman with severe AS undergoing a total mastectomy.

Case presentation

An 81-year-old woman with severe AS was scheduled to undergo a total mastectomy. We decided to administer total intravenous anaesthesia with remimazolam to minimize haemodynamic changes. Although the patient showed transient hypotension after anaesthesia induction, the cardiac index was preserved with a low dose of continuous noradrenaline. The anaesthesia was then safely maintained without a decrease in the patient’s cardiac index.

Conclusions

General anaesthesia using remimazolam preserved cardiac output in this patient; therefore, remimazolam can be safely used to avoid the risk of cardiac suppression in patients with severe AS.

Remimazolam: Non-Clinical and Clinical Profile of a New Sedative/Anesthetic Agent

A program to identify novel intravenous sedatives with a short and predictable duration of action was initiated in the late 1990's by Glaxo Wellcome. The program focussed on the identification of ester-based benzodiazepine derivatives that are rapidly broken down by esterases. Remimazolam was identified as one of the lead compounds. The project at Glaxo was shelved for strategic reasons at the late lead optimization stage. Via the GSK ventures initiative, the program was acquired by the small biotechnology company, TheraSci, and, through successive acquisitions, developed as the besylate salt at CeNeS and PAION. The development of remimazolam besylate has been slow by industry standards, primarily because of the resource limitations of these small companies. It has, however, recently been approved for anesthesia in Japan and South Korea, procedural sedation in the United States, China, and Europe, and for compassionate use in intensive care unit sedation in Belgium. A second development program of remimazolam was later initiated in China, using a slightly different salt form, remimazolam tosylate. This salt form of the compound has also recently been approved for procedural sedation in China. Remimazolam has the pharmacological profile of a classical benzodiazepine, such as midazolam, but is differentiated from other intravenous benzodiazepines by its rapid conversion to an inactive metabolite resulting in a short onset/offset profile. It is differentiated from other intravenous hypnotic agents, such as propofol, by its low liability for cardiovascular depression, respiratory depression, and injection pain. The benzodiazepine antagonist flumazenil can reverse the effects of remimazolam in case of adverse events and further shorten recovery times. The aim of this review is to provide an analysis of, and perspective on, published non-clinical and clinical information on 1) the pharmacology, metabolism, pharmacokinetics, and pharmacodynamic profile of remimazolam, 2) the profile of remimazolam compared with established agents, 3) gaps in the current understanding of remimazolam, 4) the compound's discovery and development process and 5) likely future developments in the clinical use of remimazolam.

Induction and maintenance of procedural sedation in adults: focus on remimazolam injection

Introduction: Procedural sedation (PS) is a humane way to help patients get through painful medical procedures by the administration of sedative drugs combined with analgesics. However, each of the currently used medications has certain shortcomings, urging the search for a new drug. Remimazolam, a novel benzodiazepine, is an ultra-short-acting hypnotic agent invented out of the 'soft drug' development.Areas covered: This presented review provides an overview of the drugs used in clinical practice for the induction and maintenance of procedural sedation in adults, focusing on the newly investigated benzodiazepine remimazolam. Literature search was conducted using the MEDLINE and ClinicalTrial.gov databases from January 2007 to December 2020.Expert opinion: Based on the reported clinical trials so far, remimazolam has demonstrated its effectiveness and safety with promising properties including rapid onset, short duration of action, predictable and consistent recovery profile, metabolism almost unaffected by liver or renal function, with non or minimal cardiorespiratory depression, and availability with a reversal drug. With marketing approval received recently, remimazolam is expected to have a place in the practice for procedural sedation in the near future if its efficacy and safety are further confirmed by more clinical trials and post-market analyses.

The efficacy and safety of remimazolam tosylate versus propofol in patients undergoing colonoscopy: a multicentered, randomized, positive-controlled, phase III clinical trial

This study aimed to evaluate the efficacy and safety of remimazolam tosylate versus propofol in patients undergoing colonoscopy. In this multicentered, blinded, randomized, active-controlled, non-inferior phase III trial, 384 eligible patients who were about to undergo colonoscopy were randomized as a ratio of 1:1 into remimazolam and propofol group. Procedure success was assessed and defined as the completion of colonoscopy without administration of rescue sedative agent or more than 5 top-ups of trial drug in any 15 minute-period after initial administration of trial drug. Sedation quality was evaluated by Modified Observer's Assessment of Alertness/Sedation score. Treatment-emergent adverse events were recorded. Procedure success rate was 96.91% (188/194) in remimazolam group and 100% (190/190) in propofol group, and the difference in rate was -3.09% with 95% confidence interval (CI) of -5.53%~-0.66%. Since the lower limit of 95% CI was greater than the non-inferiority margin of -8.00%, the efficacy of remimazolam tosylate was non-inferior to propofol. Besides, induction time of sedation was increased (P<0.001), while hypotension and respiratory depression was decreased in remimazolam group compared to propofol group; however, time to fully alert (P>0.05) or time to discharge (P>0.05) were unchanged. For safety assessment, total treatment-emergent adverse events were decreased in remimazolam group compared to propofol group (P<0.001); specifically, administration site pain (P<0.001), increased bilirubin (P=0.019), decreased respiratory rate (P<0.001) and decreased SpO₂ (P<0.001) were less frequent in remimazolam group compared with propofol group. In conclusion, remimazolam tosylate is non-inferior in sedation efficacy while safer than propofol in patients undergoing colonoscopy.

Efficacy and safety of remimazolam in procedural sedation and analgesia: A protocol for systematic review and meta analysis

BACKGROUND

Remimazolam is a newly developed benzodiazepine as an alternative of conventional sedatives in the procedure of anesthesia. For the purpose of evaluating the efficacy and safety of remimazolam sedation during an endoscopy, we will perform a systematic review and meta-analysis of randomized controlled trials that compared remimazolam with midazolam and/or placebo.

METHODS

We will search PubMed, Embase, Web of Science, and the Cochrane Controlled Register of Trials (CENTRAL) from inception to December 2019 for randomized controlled trials that investigated efficacy and safety of remimazolam during an endoscopy. The job will be performed without language restriction. Experimental groups will include the interventions of remimazolam, while control groups will involve midazolam, placebo, or no controls. The primary outcome will be the onset time, followed by the secondary outcomes of the recovery time, the incidence of hypotension, the incidence of hypoxia and the incidence of bradycardia. Relative ratio or standardized mean difference will be used to measure the effect size of remimazolam. We will use I statistics to assess the between-study heterogeneity in each meta-analysis, Eager's test to detect publication bias.

RESULTS

The results of this study will be published in a peer-reviewed journal.

ETHICS AND DISSEMINATION

There is no need for ethical approval because all data used in this meta-analysis have been published. In addition, all data will be analyzed anonymously during the review process.

PROTOCOL REGISTRATION NUMBER

CRD42020170745.

Novel benzodiazepines derivatives as analgesic modulating for Transient receptor potential vanilloid 1

A new series of derivatives of 3-(7-chloro-5-(2-fluorophenyl)-2-oxo-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl)propanoic acid were designed and synthesized as analgesic modulating for Transient receptor potential vanilloid 1. They were investigated for TRPV1 antagonistic activity in vitro, analgesic activity and sedative activity in vivo and aqueous solubility. Preliminary studies identified 3-(7-chloro-5-(2-fluorophenyl)-2-oxo-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl)-N,N-dimethylpropanamide(Compound 11), as a potent analgesic modulating for TRPV1 with potent activity and good aqueous solubility.

Implanted electrodes for multi-month EEG

An implanted electroencephalogram (EEG) recorder would help diagnose infrequent seizure-like events. A proof-of-concept study quantified the electrical characteristics of the electrodes planned for the proposed recorder. The electrodes were implanted in an ovine model for eight weeks. Electrode impedance was less than 800 Ohms throughout the study. A frequency-domain determination of sedation performed similarly for surface versus implanted electrodes throughout the study. The time-domain correlation between an implanted electrode and a surface electrode was almost as high as between two surface electrodes (0.86 versus 0.92). EEG-certified clinicians judged that the implanted electrode quality was adequate to excellent and that the implanted electrodes provided the same clinical information as surface electrodes except for a noticeable amplitude difference. No significant issues were found that would stop development of the EEG recorder.

Remimazolam: The future of its sedative potential

Remimazolam (CNS 7056) is a new drug innovation in anesthesia. It combines the properties of two unique drugs already established in anesthesia - Midazolam and remifentanil. It acts on GABA receptors like midazolam and has organ-independent metabolism like remifentanil. It is likely to be the sedative of the future, as preliminary phase II trials have shown minimal residual effects on prolonged infusions. It has potential to be used as a sedative in ICU and as a novel agent for procedural sedation. Unlike most rapidly acting intravenous sedatives available presently, the propensity to cause apnea is very low. Availability of a specific antagonist (flumazenil) adds to its safety even in cases of overdose. The present review discusses remimazolam's potential as a new drug in anesthesia along with the presently available literary evidence.

Age-related changes in EEG power spectra in infants during sevoflurane wash-out

BACKGROUND

Few electroencephalography (EEG) data are available in anaesthetized infants. This study aimed to identify EEG characteristics that might warn of awakening (AW) from sevoflurane anaesthesia in infants.

METHODS

Twenty intubated infants [aged 39-77 weeks post-menstrual age (PMA)] were studied after surgery during sevoflurane wash-out. EEG was recorded at the end of surgery and throughout emergence. Changes in EEG time and frequency domains were described.

RESULTS

At the end of surgery, mean end-tidal sevoflurane concentration was 2.3% (range 1.5-3.5) before wash-out and reduced to 0.3% (0.1-0.6) when AW began. On AW, movement artifacts made signals difficult to interpret. Before awakening, most power was within frequencies ≤4 Hz, but trends over time were variable. Summated power in frequencies between 20 and 70 Hz was almost always <5 µV(2). During anaesthesia, there were two common power spectra: infants >52 weeks PMA had obvious summated power in the frequency range 5-20 Hz (P5-20 Hz) (mean 308, median 320, range 110-542 µV(2)), which decreased before awakening began [mean decrease 252 µV(2) (95% CI 153-351)], whereas younger infants had low P5-20 Hz throughout. P5-20 Hz during anaesthesia increased with age; power in this frequency band of ~100 µV(2) separated infants younger and older than 52 weeks PMA.

CONCLUSIONS

During sevoflurane wash-out, decreasing P5-20 Hz might warn of impending AW in infants >3 months old, but not in younger infants.

Anesthetic drug development: Novel drugs and new approaches

The ideal sedative–hypnotic drug would be a rapidly titratable intravenous agent with a high therapeutic index and minimal side effects. The current efforts to develop such agents are primarily focused on modifying the structures of existing drugs to improve their pharmacodynamic and pharmacokinetic properties. Drugs currently under development using this rational design approach include analogues of midazolam, propofol, and etomidate, such as remimazolam, PF0713, and cyclopropyl methoxycarbonyl-etomidate (MOC-etomidate), respectively. An alternative approach involves the rapid screening of large libraries of molecules for activity in structural or phenotypic assays that approximate anesthetic and target receptor interactions. Such high-throughput screening offers the potential for identifying completely novel classes of drugs. Anesthetic drug development is experiencing a resurgence of interest because there are new demands on our clinical practice that can be met, at least in part, with better agents. The goal of this review is to provide the reader with a glimpse of the novel anesthetic drugs and new developmental approaches that lie on the horizon.

Enhancement of GABAergic activity: neuropharmacological effects of benzodiazepines and therapeutic use in anesthesiology

GABA is the major inhibitory neurotransmitter in the central nervous system (CNS). The type A GABA receptor (GABA(A)R) system is the primary pharmacological target for many drugs used in clinical anesthesia. The α1, β2, and γ2 subunit-containing GABA(A)Rs located in the various parts of CNS are thought to be involved in versatile effects caused by inhaled anesthetics and classic benzodiazepines (BZD), both of which are widely used in clinical anesthesiology. During the past decade, the emergence of tonic inhibitory conductance in extrasynaptic GABA(A)Rs has coincided with evidence showing that these receptors are highly sensitive to the sedatives and hypnotics used in anesthesia. Anesthetic enhancement of tonic GABAergic inhibition seems to be preferentially increased in regions shown to be important in controlling memory, awareness, and sleep. This review focuses on the physiology of the GABA(A)Rs and the pharmacological properties of clinically used BZDs. Although classic BZDs are widely used in anesthesiological practice, there is a constant need for new drugs with more favorable pharmacokinetic and pharmacodynamic effects and fewer side effects. New hypnotics are currently developed, and promising results for one of these, the GABA(A)R agonist remimazolam, have recently been published.

Pharmacokinetics and pharmacodynamics of the short-acting sedative CNS 7056 in sheep

BACKGROUND

CNS 7056 is a new short-acting esterase-metabolized benzodiazepine. We report the first pharmacokinetic (PK) and pharmacodynamic (PD) study of CNS 7056 and its inactive metabolite CNS 7054 in sheep.

METHODS

The stability of CNS 7056 in blood samples was examined ex vivo. Six sheep were prepared with physiological instrumentation, and were given doses of 0.37, 0.74, and 1.47 mg kg(-1) (2 min infusion) of CNS 7056 in alternating order on separate days.

RESULTS

CNS 7056 was degraded in warm whole sheep blood (23% over 2 h), but not in plasma or blood stored on ice. Using non-compartmental analysis (NCA), CNS 7056 had a mean (sd) clearance of 4.52 (0.96) litre min(-1) and a terminal half-life of 21.3 (10.9) min. There was a rapid conversion of CNS 7056 to its metabolite CNS 7054, which had a terminal half-life of 22.5 (3.4) min. The arterial kinetics of CNS 7056 could be described by a three-compartment model, with volumes of 1.9, 3.9, and 79 litre, a clearance of 4.2 litre min(-1), and inter-compartmental clearances of 2.85 and 1.44 litre min(-1), while the metabolite could be described by a two-compartment model. Cardiac output was an important covariate. Sedation as measured by the alpha power band of the EEG showed rapid onset and offset. The t(1/2,)(k)(e0) for sedation was 1.78 min, and the EC(50) was 0.10 µg ml(-1).

CONCLUSIONS

CNS 7056 has PK-PD properties compatible with its potential human use as a short-acting i.v. sedative.

Comparison of the sedative properties of CNS 7056, midazolam, and propofol in sheep

BACKGROUND

CNS 7056 is an esterase-metabolized benzodiazepine sedative currently under development. Its short duration of action would suggest a clinical role similar to midazolam or propofol.

METHODS

The effect of a range of doses of CNS 7056, midazolam, and propofol on depth of sedation, the respiratory system, and the cardiovascular system was studied in chronically instrumented sheep (n=5 or 6). The low, medium, and high doses of CNS 7056, midazolam, and propofol were 0.37, 0.74, and 1.47 mg kg(-1); 0.05, 0.1, and 0.2 mg kg(-1); and 1, 2, and 4 mg kg(-1), respectively.

RESULTS

CNS 7056 produced substantial sedation with rapid onset and offset for all doses, with duration rather than depth of sedation increasing with the dose. The lower doses of midazolam had minimal sedative effect; increasing the dose produced variable but longer term sedation. Sedation from propofol was comparable with that of CNS 7056 for the medium and high doses only. The high doses produced approximately 20 min of sedation. All three drugs produced dose-dependent respiratory (e.g. reductions in arterial oxygen tension) and cardiovascular depression (e.g. reductions in mean arterial pressure). For CNS 7056, midazolam, and propofol, the magnitude of the cardiovascular and respiratory depression was proportional to the depth of sedation achieved for any given drug or dose. For all three drugs, the respiratory and cardiovascular depression was not of sufficient magnitude to endanger the animals.

CONCLUSIONS

CNS 7056 is a powerful and short-acting anaesthetic in sheep with respiratory and cardiovascular effects consistent with its sedative/anaesthetic qualities.