Impact of concurrent remifentanil on the sedative effects of remimazolam, midazolam and propofol in cynomolgus monkeys

Electroencephalogram Correlates of Delayed Emergence After Remimazolam-Induced Anesthesia Compared to Propofol

BACKGROUND

Delayed emergence from anesthesia presents clinical challenges, including prolonged stays in the postanesthesia care unit (PACU). The neurobiological mechanisms underlying delayed emergence, particularly in remimazolam-induced anesthesia, remain poorly understood. This study aimed to explore patterns of brain electrical activity of delayed emergence in remimazolam-induced anesthesia by comparing dynamic changes in electroencephalogram (EEG) activity under various anesthesia states of remimazolam and propofol, focusing on the prefrontal region.

METHODS

Forty-eight patients (age >18) who underwent laparoscopic cholecystectomy randomly received remimazolam- or propofol-induced general anesthesia. Power spectrogram analysis and functional connectivity measures, phase lag entropy (PLE) and phase lag index (PLI), were used to the prefrontal EEG data collected at baseline, unconsciousness, and emergence. Correlation between EEG measures and Patient State Index (PSI) at PACU, as well as time to Aldrete 9, were compared.

RESULTS

During emergence from anesthesia, EEG power revealed that the remimazolam group had higher powers than the propofol group in theta band during eyes-open (EO) (mean of 2.933 [standard deviation of 5.762] vs -2.342 [4.869]; P-value of 0.018 with independent 2-sample t test), and in the alpha band during eyes-closed (EC) (5.821 [7.35] vs -2.399 [4.53]; P < .001) and EO (4.84 [6.411] vs -3.613 [4.556]; P < .001). Conversely, the functional connectivity result showed lower PLE in the alpha band during EC (0.619 [0.0338] vs 0.684 [0.0392]; P < .0001) and EO (0.651 [0.0358] vs 0.692 [0.0428]; P = .015), and in the beta band during EC (0.682 [0.0308] vs 0.712 [0.0236]; P = .016) and EO (0.695 [0.0236] vs 0.725 [0.0195]; P < .001). In line with this, the remimazolam group had lower PSI values at PACU during EC (65.10 [14.67] vs 82.40 [6.678]; P < .0001) and EO (72.35 [12.55] vs 83.53 [6.632]; P = .006) and were slower to reach Aldrete score of 9 (median difference of 17.5; interquartile range of [0.0-21.0]; P < .001). Delayed consciousness recovery (time to Aldrete 9) under remimazolam was significantly correlated with PLE (Pearson's correlation = -.78, P < .0001) and PLI (Pearson's correlation =.69, P = .028) in the alpha band during deep anesthesia.

CONCLUSIONS

Dynamic changes in prefrontal EEG during recovery and the correlation analyses show the potential of EEG in reflecting distinct consciousness recovery profiles between 2 drugs-slower recovery under remimazolam anesthesia. This suggests an association of EEG parameters with a unique behavioral profile of remimazolam, especially reflecting progressive changes in cerebral activity during recovery.

Impact of genetic polymorphisms and drug-drug interactions mediated by carboxylesterase 1 on remimazolam deactivation

Remimazolam (Byfavo, Acacia Pharma), a recent Food and Drug Administration-approved ester-linked benzodiazepine, offers advantages in sedation, such as rapid onset and predictable duration, making it suitable for broad anesthesia applications. Its favorable pharmacological profile is primarily attributed to rapid hydrolysis, the primary metabolism pathway for its deactivation. Thus, understanding remimazolam hydrolysis determinants is essential for optimizing its clinical use. This study aimed to identify the enzyme(s) and tissue(s) responsible for remimazolam hydrolysis and to evaluate the influence of genetic polymorphisms and drug-drug interactions on its hydrolysis in the human liver. An initial incubation study with remimazolam and PBS, human serum, and the S9 fractions of human liver and intestine demonstrated that remimazolam was exclusively hydrolyzed by human liver S9 fractions. Subsequent incubation studies utilizing a carboxylesterase inhibitor (bis(4-nitrophenyl) phosphate), recombinant human carboxylesterase 1 (CES1) and carboxylesterase 2 confirmed that remimazolam is specifically hydrolyzed by CES1 in human liver. Furthermore, in vitro studies with wild-type CES1 and CES1 variants transfected cells revealed that certain genetic polymorphisms significantly impair remimazolam deactivation. Notably, the impact of CES1 G143E was verified using individual human liver samples. Moreover, our evaluation of the drug-drug interactions between remimazolam and several other substrates/inhibitors of CES1-including simvastatin, enalapril, clopidogrel, and sacubitril-found that clopidogrel significantly inhibited remimazolam hydrolysis at clinically relevant concentrations, with CES1 genetic variants potentially influencing the interactions. In summary, CES1 genetic variants and its interacting drugs are crucial factors contributing to interindividual variability in remimazolam hepatic hydrolysis, holding the potential to serve as biomarkers for optimizing remimazolam use. SIGNIFICANCE STATEMENT: This investigation demonstrates that remimazolam is deactivated by carboxylesterase 1 (CES1) in the human liver, with CES1 genetic variants and drug-drug interactions significantly influencing its metabolism. These findings emphasize the need to consider CES1 genetic variability and potential drug-drug interactions in remimazolam use, especially in personalized pharmacotherapy to achieve optimal anesthetic outcomes.

Remimazolam

Remimazolam is a new reversible γ-aminobutyric acid type A agonist benzodiazepine that displays a fast onset of action, short recovery time with a safe cardiopulmonary profile and favorable pharmacokinetics in comparison with other intravenous sedatives.

Remimazolam in General Anesthesia: A Comprehensive Review of Its Applications and Clinical Efficacy

Remimazolam is a novel ultra-short-acting benzodiazepine with a unique pharmacokinetic profile that makes it an attractive option for use in general anesthesia. This review paper provides an in-depth analysis of remimazolam's applications in the field of general anesthesia, focusing on its pharmacological properties, clinical efficacy, safety profile, and potential advantages compared to other anesthetic agents. Remimazolam acts on GABAa receptors, offering rapid onset and recovery times due to its unique metabolic pathway involving tissue esterases. Clinical trials have demonstrated its efficacy in procedural sedation and general anesthesia, showing a favorable safety profile with minimal cardiovascular and respiratory depression. Compared to traditional anesthetics such as propofol, remimazolam presents distinct advantages, including predictable pharmacokinetics, reduced risk of prolonged sedation, and a reliable safety margin. These attributes position remimazolam as a promising agent in various clinical settings. The purpose of this review is to synthesize current evidence on remimazolam and discuss its potential to improve clinical outcomes in anesthesia practice.

Successful use of remimazolam combined with remifentanil for painless gastroscopy in a patient with morbid obesity: a case report

Backgroud

In recent years, as the number of people with obesity has surged, the number of morbidly obese patients has also grown. The pathophysiological changes in morbid obesity can lead to combined lung diseases, which may result in hypoventilation, hypoxemia, acute upper airway obstruction, acute respiratory distress syndrome, and sleep apnea syndrome, posing serious challenges to anesthesia management. Here, we describe a case of the administration of remimazolam combined with remifentanil in a patient with morbid obesity undergoing gastroscopy. This has rarely been reported in clinical practice, and we present our management experience here with the aim of providing a reference for clinical work.

Case presentation

We report the case of a 32-year-old male hypertensive patient with a height of 180 cm, weight of 145 kg, and body mass index of 44.8 kg/m2. The patient's main complaint was intermittent hunger pain for more than 1 year, and duodenal polyps were found. Considering the patient's morbid obesity and the combination of sleep apnea syndrome and hypertension, we administered remimazolam along with remifentanil to ensure perioperative safety.

Conclusion

The procedure lasted 30 min, and the anesthesia was satisfactory with no complications. Remimazolam combined with remifentanil intravenous anesthesia is safe for short gastroscopy in patients with morbidly obesity. The administration of a small dose of split-titration delivery facilitates the maintenance of stable vital signs.

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.

Effectiveness and safety of remimazolam combined with alfentanil in hysteroscopic examination: A prospective, randomized, single-blind trial

BACKGROUND

Remimazolam is a novel, ultrashort-acting benzodiazepine. This study aimed to compare the efficacy and safety of remimazolam and propofol for hysteroscopic examination, to determine the optimal dose of remimazolam combined with alfentanil for painless hysteroscopy, and to calculate its median effective dose (ED50).

METHODS

Step 1: A total of 208 patients undergoing hysteroscopic examination were prospectively included in this study. Patients were randomized into 4 groups: 0.2 mg/kg remimazolam (group A), 0.25 mg/kg remimazolam besylate (group B), 0.3 mg/kg remimazolam (group C), and 2 mg/kg propofol (group D), with 52 patients in each group. One minute after losing consciousness, patients received an intravenous injection of alfentanil at 5 µg/kg, followed by a continuous infusion of alfentanil at 0.5 µg/kg/min. If patients showed frowning, movement, or MOAA/S > 1, sedatives were added: 0.05 mg/kg/dose of remimazolam for groups A, B, and C, and 0.5 mg/kg/dose of propofol for group D. Step 2: Dixon's up-and-down method was used to calculate the ED50 of remimazolam combined with alfentanil during hysteroscopic examination.

MAIN RESULTS

The sedation success rates of the remimazolam groups were 88.46%, 94.23%, and 98.08%, respectively, compared to 96.15% in the propofol group, with no significant difference (P = .175). MAP in groups A and B was higher than in group D (P < .05), and significantly higher in group C than in group D (P = .0016). SpO2 values in groups A, B, and C were higher than in group D at T2 to T3 (P < .001). HR in groups A, B, and C was significantly higher than in group D (P < .001). The ED50 of remimazolam combined with alfentanil in hysteroscopy was 0.244 mg/kg, 95%CI (0.195-0.22) and ED95 was 0.282 mg/kg, 95%CI (0.261-1.619).

CONCLUSION

In hysteroscopy, the sedative effect of remimazolam is like that of propofol, with 0.25 mg/kg remimazolam showing better safety and efficacy, and less impact on the respiratory and circulatory systems. Additionally, under the influence of alfentanil, the ED50 of remimazolam in hysteroscopy is 0.244 mg/kg, with no severe adverse reactions observed.

Efficacy of remimazolam tosilate versus propofol for total intravenous anaesthesia in urological surgery: A randomised clinical trial

BACKGROUND

Remimazolam is a novel ultra-short-acting benzodiazepine sedative that acts on the gamma-aminobutyric acid type A receptor (GABAAR).

OBJECTIVE

To compare the efficacies of remimazolam (RMZ), and propofol (PROP) combined with remifentanil and cisatracurium for total intravenous anaesthesia (TIVA) in patients undergoing urological surgery.

DESIGN

A prospective, single-blind, randomised, noninferiority clinical trial.

SETTING

Single centre from 1 January 2022 to 30 March 2022.

PATIENTS

A total of 146 adult patients undergoing elective urological surgery.

INTERVENTION

Patients were randomly allocated in a 1 : 1 ratio to the PROP or RMZ groups. In the PROP group, anaesthesia was induced with propofol at 100 mg min -1 to reach a bispectral index score (BIS) of 40 to 60. After loss of consciousness (LOC), intravenous fentanyl 3 μg kg -1 was administered, followed by cisatracurium 0.3 mg kg -1 . Patients were intubated 3 min after cisatracurium administration. Anaesthesia was maintained with the combination of propofol (plasma concentration: 2.5 to 4 μg ml -1 ) and remifentanil (plasma concentration: 2.5 to 4 ng ml -1 ). In the RMZ group, anaesthesia was induced with remimazolam tosilate starting at 10 mg kg -1  h -1 to reach a BIS of 40 to 60 and maintained between 0.2 and 2 mg kg -1  h -1 . After LOC, fentanyl and cisatracurium were administered and intubation was performed as in the PROP group. Anaesthesia was maintained with a combination of remimazolam (0.2 to 2 mg kg -1  h -1 ) and remifentanil (plasma concentration: 2.5 to 4 ng ml -1 ).

MAIN OUTCOME MEASURES

The primary outcome was the TIVA success rate. The predefined noninferiority margin considered an absolute difference of 6% in the primary outcome between the groups. The secondary outcomes were vital signs, anaesthesia and surgery characteristics, and adverse events.

RESULTS

All patients completed the trial. The success rates of TIVA with remimazolam and propofol were 100 and 98.6%, respectively. The incidence of hypotension during anaesthesia was lower in the RMZ group (26%) than in the PROP group (46.6%) ( P  = 0.016). The median [IQR] total consumption of ephedrine during anaesthesia was higher in the PROP group 10 [0 to 12.5] mg than in the RMZ group 0 [0 to 10] mg ( P  = 0.0002). The incidence of injection pain was significantly higher in the PROP group (76.7%) than in the RMZ group (0; P  < 0.001). No significant differences in the controllability of the anaesthesia depth, anaesthesia and surgery characteristics, or vital signs were observed between the groups.

CONCLUSION

Remimazolam demonstrated noninferior efficacy to propofol combined with remifentanil and cisatracurium for TIVA in patients undergoing urological surgery.

TRIAL REGISTRATION

Chictr.org.cn, identifier: ChiCTR2100050923.

CLINICAL REGISTRATION

The study was registered in the Chinese Clinical Trial Registry (ChiCTR2100050923, Principal investigator: Xuehai Guan, Date of registration: 8 November 2021, https://www.chictr.org.cn/showproj.html?proj=133466 ).

Drug-Drug Interaction Potential of Remimazolam: CYP 450, Transporters, and Protein Binding

BACKGROUND

The ultra-short-acting benzodiazepine, remimazolam, is a new treatment modality for procedural sedation and general anesthesia. Its activity is terminated by carboxylesterase 1 (CES1).

OBJECTIVE

The objective of this study was to determine the drug-drug interaction (DDI) potential of remimazolam through mechanisms unrelated to its metabolizing enzyme, CES1.

METHODS

Conventional in vitro co-exposure experiments were conducted to study possible interactions of remimazolam and its primary metabolite, CNS7054, mediated by competitive binding to plasma protein or reactions with cytochrome P450 isoforms or drug transporters.

RESULTS

No relevant interactions of remimazolam or its metabolite with cytochrome P450 (CYP) isoforms at clinically relevant concentrations were identified. Likewise, standard experiments revealed no clinically relevant interactions with drug transporters and plasma proteins.

CONCLUSION

The present data and analyses suggest a very low potential of remimazolam for pharmacokinetic DDIs mediated by CYP isoforms, drug transporters, and protein binding.

Randomized controlled trial for anesthesia during gastroscopy: interactions between remimazolam and propofol in combination with sufentanil

BACKGROUND

Remimazolam is a new short-duration anesthetic currently used for gastroscopy and can be mixed with propofol and potent opioids.

AIM

The study aimed to investigate the synergistic interaction between remimazolam and propofol after sufentanil administration and to determine the appropriate dose ratios between remimazolam and propofol.

METHOD

This study used a randomized controlled design. Patients scheduled for gastrointestinal endoscopy were included and randomized into five groups. The randomized block design was applied at a randomization ratio of 1:1. Patients in each group received sufentanil (0.1 μg/kg) and the calculated doses of remimazolam and propofol. Using the up and down method, the median effective dose (ED50) and the 95% confidence interval (CI) were determined based on whether the eyelash reflex disappeared in each treatment group. Isobolographic analysis was used to analyze the presence of drug interactions. The interaction coefficient and the dose ratio between remimazolam and propofol were calculated by algebraic analysis. Statistical analysis was performed using interval estimates and 95% CI for statistical attributes.

RESULTS

Cross-sectional analysis of the isobologram showed a clinically significant synergistic effect between remimazolam and propofol. When 0.016, 0.032, and 0.047 mg/kg of remimazolam were combined with 0.477, 0.221, and 0.131 mg/kg of propofol, the interaction coefficients were 1.04, 1.21, and 1.06, respectively. The dose ratio of remimazolam to propofol was approximately 1:7.

CONCLUSION

Remimazolam and propofol have synergistic clinical effects. A strong synergistic effect was observed when the remimazolam and propofol dose ratio was 1:7 (mg/kg).

CLINICAL TRIAL

The study protocol was registered at the Chinese Clinical Trial Registry (ChiCTR2100052425).

Effective dose of remimazolam co-administered with remifentanil to facilitate I-gel insertion without neuromuscular blocking agents: an up-and-down sequential allocation trial

BACKGROUND

Remimazolam is a new anesthetic drug developed and is an ultra-short-acting agent with rapid onset and offset. The pharmacology of this drug seems to be ideal for short surgeries eligible for I-gel insertion. Therefore, this study aimed to determine the optimal bolus dose of remimazolam for I-gel insertion when co-administered with remifentanil without neuromuscular blocking agents (NMBAs).

METHODS

Patients aged 19-65 years with American Society of Anesthesiologists physical status I or II scheduled for general anesthesia were enrolled. The first dose of remimazolam was 0.15 mg/kg and remifentanil was co-administered at an effect-site concentration (Ce) of 3.0 ng/mL. The dose of remimazolam for the following patient was decreased or increased by 0.05 mg/kg depending on the success or failure of I-gel insertion in the previous patient.

RESULTS

The remimazolam bolus dose required for successful I-gel insertion in 50% of adult patients using modified Dixon's up-and-down method with remifentanil Ce 3.0 ng/mL and no NMBAs was 0.280 ± 0.048 mg/kg. Isotonic regression analysis showed that the 50% and 95% effective doses were 0.244 (83% confidence interval [CI] 0.213-0.313) mg/kg and 0.444 (95% CI 0.436-0.448) mg/kg, respectively. The mean time to loss of consciousness (Modified Observer's Assessment of Alertness/Sedation score < 2) was 52.2 s. Three patients (12.0%) showed a reduction in systolic blood pressure of more than 30% from baseline.

CONCLUSIONS

Selecting the appropriate dose of remimazolam/remifentanil without NMBAs makes it feasible to insert the I-gel.

TRIAL REGISTRATION

This study protocol was registered at http://cris.nih.go.kr (KCT0007801, 12th, October, 2022).

Efficacy and safety of remimazolam besylate in bronchoscopy for adults: A multicenter, randomized, double-blind, positive-controlled clinical study

Background: With the development of fiberoptic bronchoscopy in the diagnosis and treatment of various pulmonary diseases, the anesthesia/sedation requirements are becoming more demanding, posing great challenges for patient safety while ensuring a smooth examination/surgery process. Remimazolam, a brand-new ultra-short-acting anesthetic, may compensate for the shortcomings of current anesthetic/sedation strategies in bronchoscopy.

Methods: This study was a prospective, multicenter, randomized, double-blind, parallel positive controlled phase 3 clinical trial. Subjects were randomized to receive 0.2 mg/kg remimazolam besylate or 2 mg/kg propofol during bronchoscopy to evaluate the efficacy and safety of remimazolam.

Results: A total of 154 subjects were successfully sedated in both the remimazolam group and the propofol group, with a success rate of 99.4% (95%CI of the adjusted difference −6.7 × 10%–6% to −5.1 × 10%–6%). The sedative effect of remimazolam was noninferior to that of propofol based on the prespecified noninferiority margin of −5%. Compared with the propofol group, the time of loss of consciousness in the remimazolam group (median 61 vs. 48s, p < 0.001), the time from the end of study drug administration to complete awakening (median 17.60 vs. 12.80 min, p < 0.001), the time from the end of bronchoscopy to complete awakening (median 11.00 vs. 7.00 min, p < 0.001), the time from the end of study drug administration to removal of monitoring (median 19.50 vs. 14.50 min, p < 0.001), and the time from the end of bronchoscopy to removal of monitoring (median 12.70 vs. 8.60 min, p < 0.001) were slightly longer. The incidence of Adverse Events in the remimazolam group and the propofol group (74.8% vs. 77.4%, p = 0.59) was not statistically significant, and none of them had Serious Adverse Events. The incidence of hypotension (13.5% vs. 29.7%, p < 0.001), hypotension requiring treatment (1.9% vs. 7.7%, p = 0.017), and injection pain (0.6% vs. 16.8%, p < 0.001) were significantly lower in the remimazolam group than in the propofol group.

Conclusion: Moderate sedation with 0.2 mg/kg remimazolam besylate is effective and safe during bronchoscopy. The incidence of hypotension and injection pain was less than with propofol, but the time to loss of consciousness and recovery were slightly longer.

Clinical Trial Registration:clinicaltrials.gov, ChiCTR2000039753

Novel anesthetics in pediatric practice: is it time?

PURPOSE OF REVIEW

Steadily mounting evidence of anesthesia-induced developmental neurotoxicity has been a challenge in pediatric anesthesiology. Considering that presently used anesthetics have, in different animal models, been shown to cause lasting behavioral impairments when administered at the peak of brain development, the nagging question, 'Is it time for the development of a new anesthetic' must be pondered.

RECENT FINDINGS

The emerging 'soft analogs' of intravenous anesthetics aim to overcome the shortcomings of currently available clinical drugs. Remimazolam, a novel ester-analog of midazolam, is a well tolerated intravenous drug with beneficial pharmacological properties. Two novel etomidate analogs currently in development are causing less adrenocortical suppression while maintaining equally favorable hemodynamic stability and rapid metabolism. Quaternary lidocaine derivatives are explored as more potent and longer lasting alternatives to currently available local anesthetics. Xenon, a noble gas with anesthetic properties, is being considered as an anesthetic-sparing adjuvant in pediatric population. Finally, alphaxalone is being reevaluated in a new drug formulation because of its favorable pharmacological properties.

SUMMARY

Although a number of exciting anesthetic drugs are under development, there is currently no clear evidence to suggest their lack of neurotoxic properties in young brain. Well designed preclinical studies are needed to evaluate their neurotoxic potential.

Efficacy of remimazolam versus midazolam for procedural sedation: post hoc integrated analyses of three phase 3 clinical trials

Background and study aims  Remimazolam is an ultra-short acting, fast onset/fast offset benzodiazepine for intravenous use in procedural sedation, general anesthesia, and Intensive Care Unit sedation. The aim of this work was to compare the efficacy of remimazolam versus midazolam dosed according to medical practice (real-world midazolam) and midazolam dosed according to US prescribing information (on-label midazolam) for procedural sedation. Patients and methods  This post hoc analysis was performed using integrated data from three randomized, placebo, and active (midazolam) controlled, phase 3 clinical trials in patients undergoing colonoscopy and bronchoscopy. Statistical comparisons between treatment groups, without adjustment for potential confounding factors, were exploratory and observational in nature. Results  The mean ± SD dose of midazolam in the real-world midazolam group was 6.2 ± 3.1 mg, compared with 3.5 ± 1.5 mg in the on-label midazolam group. remimazolam showed significantly shorter time from first dose to start of procedure (median 3 minutes) compared to on-label midazolam (median 8 minutes). Recovery time from end of procedure to fully alert was significantly shorter for remimazolam (median 6 minutes) than real-world midazolam (median 14 minutes), enabling earlier transfer of patients from the procedure room to the recovery area with a lower requirement for patient monitoring. The onset and recovery times with remimazolam showed significantly less inter-patient variability than with on-label midazolam and real-world midazolam, respectively. Patients treated with remimazolam received significantly less fentanyl for analgesia (78.2 ± 28.4 µg) than did those treated with real-world midazolam (113.6 ± 60.1 µg) and on-label midazolam (92.5 ± 40.0 µg). Conclusions  Remimazolam offers advantages over midazolam in terms of faster recovery and less fentanyl requirement, which may facilitate increased procedural throughput in clinical practice.

The Efficacy and Safety of Remimazolam Tosilate versus Etomidate-Propofol in Elderly Outpatients Undergoing Colonoscopy: A Prospective, Randomized, Single-Blind, Non-Inferiority Trial

Objective

The optimal sedation regime during endoscopy remains controversial, especially for elderly outpatients. In this study, we compared the efficacy and safety between remimazolam tosilate (RT) and etomidate-propofol (EP) in elderly outpatients undergoing colonoscopy.

Methods

A total of 260 elderly outpatients undergoing sedative colonoscopy were randomized into two groups. Patients in the RT group received a 0.075-mg/kg maintenance dose of remimazolam following an initial dose of 0.15 mg/kg, whereas patients in the EP group (10 mL:20 mg etomidate plus 10 mL:100 mg propofol) received a 0.05-mL/kg maintenance dose following an initial dose of 0.1 mL/kg to maintain a Modified Observer’s Assessment of Alertness/Sedation score of ≤3 during the procedure. The primary endpoint was the success of the procedure. Secondary endpoints included time metrics, hemodynamics, consumption of fentanyl, etomidate, propofol, and remimazolam, intraoperative body movement, patient and endoscopist satisfaction scores, supplemental dose of sedative and fentanyl, and incidence and severity of adverse events.

Results

The procedure success rate was 96.52% in the RT group and 100% in the EP group. The difference in procedure success rate between the RT and EP groups was −3.48% (95% confidence interval: −6.81%, −0.15%). Four patients in the RT group required rescue midazolam. Compared with patients in the RT group, the onset time of the EP group was significantly lower (p < 0.05), whereas time to fully alert (p = 0.001), ready for discharge (p = 0.001), and hospital discharge (p = 0.002) were all significantly higher in the EP group. However, there were no significant differences in procedure time (p = 0.846) or cecal intubation time (p = 0.320) between the two groups. Although the frequency of intraoperative body movement was higher in the RT group, the difference was not significant (p = 0.508). There were no significant differences in patients’ demographic and baseline characteristics, supplemental doses of sedative and fentanyl, or patient and endoscopist satisfaction scores (p > 0.05). Muscular tremor and pain on injection were recorded more frequently in the EP group (p < 0.05). However, there were no significant differences in hypoxia, respiratory depression, or incidence of postoperative nausea and vomiting. The severity of adverse events was all mild (grade 1) across both groups.

Conclusion

RT may have non-inferior efficacy and a higher safety profile than EP in elderly outpatients undergoing colonoscopy, which suggests that RT may be more suitable for elderly outpatients undergoing colonoscopy.

Interaction of remimazolam benzenesulfonate and human serum albumin: a simulated physiological study

Here, to elucidate the interaction mechanism and physicochemical properties of remimazolam and human serum albumin interactions, techniques such as fluorescence, circular dichroism (CD) spectroscopy, and isothermal titration calorimetry have been applied for study. The thermodynamic parameters at body temperature (ΔS = -207 J·mol^-1 ·K^-1 , ΔS = -9.76 × 10⁴  J·mol^-1 and ΔG = -3.34 × 10⁴  J·mol^-1 ; 310 K) manifests one strong binding site on the protein, which was modulated by van der Waals forces and hydrogen bonds. What is more, the results of CD, synchronous and three-dimensional fluorescence showed that remimazolam altered the microenvironment of the protein amino acid residues. A distance of 2.1 nm between the remimazolam and Trp shows the potential for resonance energy transfer. Furthermore, these results potentially provide information for illustrating the pharmacodynamics and toxicodynamics of remimazolam when it is applied clinically.

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.