Sugammadex, a new reversal agent for neuromuscular block induced by rocuronium in the anaesthetized Rhesus monkey †

Sugammadex for reversal of moderate-to-deep rocuronium block in a clinical setting: A retrospective report of 10 dogs

OBJECTIVE

To compare recovery times of sugammadex with spontaneous recovery from rocuronium-induced neuromuscular block (NMB) in dogs.

STUDY DESIGN

Retrospective, unmatchedcase-control study.

ANIMALS

A total of 10 dogs administered sugammadex and 10 dogs recovering spontaneously from rocuronium-induced NMB.

METHODS

Files of dogs administered rocuronium between March and August 2023 were inspected. The train-of-four (TOF) count at the time of sugammadex administration and the time between administration and TOF ratio >90% (recovery time) were recorded. The recovery time for those not administered reversal agents was considered from the first TOF value >0 until TOF ratio >90%. The dose of sugammadex and the cumulative dose of rocuronium were recorded. Rocuronium doses and recovery times were compared using Mann-Whitney tests. The coefficient of determination (R2) between the cumulative rocuronium dose and sugammadex dose and the recovery time were calculated.

RESULTS

Dogs in the sugammadex and spontaneous recovery groups were administered intravenously (IV) 0.76 (0.4-2.6) and 0.61 (0.3-2.9) mg kg-1 of rocuronium, respectively (p = 0.325). Recovery time after 3.9 (2.9-5.5) mg kg-1 of sugammadex IV was 1 (1-3) minutes and was 20 (10-35) min for spontaneous recovery (p < 0.0001). The R2 for rocuronium and sugammadex doses and recovery times were 0.19 (p = 0.2) and 0.012 (p = 0.758).

CONCLUSIONS AND CLINICAL RELEVANCE

Sugammadex 2.9-5.5 mg kg-1 reversed moderate (TOF count 1-3) or deep (TOF count 0) rocuronium-induced NMB within 3 minutes, substantially faster than spontaneous recovery.

Sugammadex for reversal of rocuronium-induced neuromuscular blockade during alfaxalone anesthesia in dogs

OBJECTIVE

To investigate the reversal effect of sugammadex on neuromuscular blockade induced by a single bolus of rocuronium in dogs under alfaxalone anesthesia.

STUDY DESIGN

Randomized, prospective, crossover experimental study.

ANIMALS

A group of six adult Beagle dogs (three females and three males), weighing 11.3-15.8 kg and aged 6-8 years, were used.

METHODS

Dogs were anesthetized twice with a 1.25 times minimum infusion rate of alfaxalone, with a washout period of at least 14 days between experiments. Neuromuscular function was monitored using acceleromyography with train-of-four (TOF) stimulation of the peroneal nerve. After recording the control TOF ratio (TOFRC), rocuronium (0.5 mg kg-1) was administered intravenously. Subsequently, sugammadex (4 mg kg-1) or an equal volume of saline (control treatment) was administered intravenously when the TOF count returned from 0 to 1 after neuromuscular blockade. Time from rocuronium injection to TOF count = 0 (onset time), time from TOF count = 0 to TOF count = 1 (maximum blockade period), time of first twitch amplitude recovery from 0.25 to 0.75 (recovery index), and time from sugammadex or saline administration to TOF ratio/TOFRC ≥ 0.9 (recovery time) were recorded.

RESULTS

The onset time and maximum blockade duration did not differ between sugammadex treatment [1.2 (0.7-1.5) minutes and 9.9 (6.3-10.5) minutes, respectively] and control treatment [median (range); 1.0 (0.7-1.1) minutes and 9.9 (8.8-11.5) minutes, respectively] (p = 0.219 and 0.844, respectively). Recovery index was 0.5 (0.3-0.7) minutes in sugammadex treatment, which was shorter than that in control treatment [4.5 (3.7-4.9) minutes] (p = 0.031). Recovery time was 0.8 (0.5-2.8) minutes in sugammadex treatment, which was shorter than that in control treatment [10.5 (6.8-14.3) minutes] (p = 0.031).

CONCLUSIONS AND CLINICAL RELEVANCE

Rocuronium-induced neuromuscular blockade was effectively reversed by sugammadex in dogs anesthetized with alfaxalone.

Highly Water-Soluble Cucurbit[8]uril Derivative as a Broad-Spectrum Neuromuscular Block Reversal Agent

Broad-spectrum agents for the reversal of residual curarization induced by neuromuscular blocking agents are of great significance. Here, we report a highly water-soluble cucurbit[8]uril (CB[8]) derivative as a broad-spectrum neuromuscular block reversal agent induced by both benzylisquinolinium and aminosteroid neuromuscular block agents by the supramolecular sequestration strategy. The UV/Vis competition titration assays suggest the high binding affinity of the CB[8] derivative toward both benzylisquinolinium-type cisatracurium besylate and aminosteroid-type rocuronium, vecuronium, and pancuronium, at the level of 10⁷ M^-1. In vivo studies demonstrate that the administration of the CB[8] derivative could significantly accelerate the recovery time compared to the placebo or neostigmine groups. The reversal activity of the CB[8] derivative is comparable to or higher than that of clinically approved sugammadex. Acute toxicity evaluations reveal that the CB[8]-derivative displays outstanding biocompatibility, with the maximum tolerance dose as high as 960 mg kg^-1.

Characterizing the Heart Rate Effects From Administration of Sugammadex to Reverse Neuromuscular Blockade: An Observational Study in Patients

BACKGROUND

Reversal of neuromuscular blockade (NMB) with sugammadex can cause marked bradycardia and asystole. Administration of sugammadex typically occurs in a dynamic period when anesthetic adjuvants and gas concentrations are being titrated to achieve emergence. This evaluation examined the heart rate (HR) responses to sugammadex to reverse moderate to deep NMB during a steady-state period and sought mechanisms for HR changes.

METHODS

Patients with normal sinus rhythm, who were undergoing elective surgery that included rocuronium for NMB, were evaluated. After surgery, while at steady-state surgical depth anesthesia with sevoflurane and mechanical ventilation, patients received either placebo or 2 or 4 mg/kg of sugammadex to reverse moderate to deep NMB. Study personnel involved in data analysis were blinded to treatment. Continuous electrocardiogram (ECG) was recorded from the 5 minutes before and 5 minutes after sugammadex/placebo administration. R-R intervals were converted to HR and averaged in 1-minute increments. The maximum prolongation of an R-R interval after sugammadex was converted to an instantaneous HR.

RESULTS

A total of 63 patients were evaluated: 8 received placebo, and 38 and 17 received 2 and 4 mg/kg sugammadex. Age, body mass index, and patient factors were similar in groups. Placebo did not elicit HR changes, whereas sugammadex caused maximum instantaneous HR slowing (calculated from the longest R-R interval), ranging from 2 to 19 beats/min. There were 7 patients with maximum HR slowing >10 beats/min. The average HR change and 95% confidence interval (CI) during the 5 minutes after 2 mg/kg sugammadex were 3.1 (CI, 2.3-4.1) beats/min, and this was not different from the 4 mg/kg sugammadex group (4.1 beats/min [CI, 2.5-5.6]). HR variability derived from the standard deviation of consecutive R-R intervals increased after sugammadex.

CONCLUSIONS

Sugammadex to reverse moderate and deep NMB resulted in a fast onset and variable magnitude of HR slowing in patients. A difference in HR slowing as a function of dose did not achieve statistical significance. The observational nature of the investigation prevented a full understanding of the mechanism(s) of the HR slowing.

Template-Directed Synthesis of Bivalent, Broad-Spectrum Hosts for Neuromuscular Blocking Agents*

We report on the synthesis of bivalent water-soluble calix[4]arene and calix[5]arene hosts, Super-sCx4 and Super-sCx5 as new broad-spectrum supramolecular binders of neuromuscular blocking agents (NMBAs). Synthesis was achieved using the target bisquaternary amine NMBAs as a template to link two highly anionic p-sulfonatocalixarene building blocks in aqueous solution. Bivalent anionic hosts Super-sCx4 and Super-sCx5 bind by engaging both quaternary amines present on a variety of NMBAs. We report low μM binding to structurally diverse alkyl, steroidal, curarine and benzylisoquinoline NMBAs with high selectivity over the neurotransmitter acetylcholine and a variety of other hydrophobic amines.

A randomized trial evaluating the safety profile of sugammadex in high surgical risk ASA physical class 3 or 4 participants

BACKGROUND

The aim of this randomized, double-blind trial was to evaluate the safety and tolerability profile, including cardiac safety, of sugammadex-mediated recovery from neuromuscular block in participants undergoing surgery who met the American Society of Anesthesiologists (ASA) Physical Class 3 or 4 criteria. Specifically, this study assessed the impact of sugammadex on cardiac adverse events (AEs) and other prespecified AEs of clinical interest.

METHODS

Participants meeting ASA Class 3 and 4 criteria were stratified by ASA Class and NMBA (rocuronium or vecuronium) then randomized to one of the following: 1) Moderate neuromuscular block, sugammadex 2 mg/kg; 2) Moderate neuromuscular block, neostigmine and glycopyrrolate (neostigmine/glycopyrrolate); 3) Deep neuromuscular block, sugammadex 4 mg/kg; 4) Deep neuromuscular block, sugammadex 16 mg/kg (rocuronium only). Primary endpoints included incidences of treatment-emergent (TE) sinus bradycardia, TE sinus tachycardia and other TE cardiac arrhythmias.

RESULTS

Of 344 participants randomized, 331 received treatment (61% male, BMI 28.5 ± 5.3 kg/m², age 69 ± 11 years). Incidence of TE sinus bradycardia was significantly lower in the sugammadex 2 mg/kg group vs neostigmine/glycopyrrolate. The incidence of TE sinus tachycardia was significantly lower in the sugammadex 2 and 4 mg/kg groups vs neostigmine/glycopyrrolate. No significant differences in other TE cardiac arrythmias were seen between sugammadex groups and neostigmine/glycopyrrolate. There were no cases of adjudicated anaphylaxis or hypersensitivity reactions in this study.

CONCLUSIONS

Compared with neostigmine/glycopyrrolate, incidence of TE sinus bradycardia was significantly lower with sugammadex 2 mg/kg and incidence of TE sinus tachycardia was significantly lower with sugammadex 2 mg/kg and 4 mg/kg. These results support the safety of sugammadex for reversing rocuronium- or vecuronium-induced moderate and deep neuromuscular block in ASA Class 3 or 4 participants.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03346057 .

Efficiency and Safety of the Selective Relaxant Binding Agent Adamgammadex Sodium for Reversing Rocuronium-Induced Deep Neuromuscular Block: A Single-Center, Open-Label, Dose-Finding, and Phase IIa Study

Background: Rapid reversal of neuromuscular block after surgery and anesthesia is often necessary. Here, we reported the primary efficacy and safety data from a phase IIa study on adamgammadex sodium, a newly developed modified γ-cyclodextrin derivative.

Methods: This was a phase IIa, single-center, randomized, open-label, and dose-finding study that enrolled 35 patients under general anesthesia who received the neuromuscular blocking agent rocuronium for induction and maintenance of neuromuscular blockade. The subjects were randomized to one of the five adamgammadex dose groups (2, 4, 6, 8, and 10 mg kg⁻¹) and to the 4 mg kg⁻¹ sugammadex group. Pharmacological efficacy was the recovery time from the start of adamgammadex or sugammadex administration to train-of-four (TOF) ratio ≥0.9, 0.8, and 0.7 among the different dose groups. Adverse events were recorded throughout the study.

Results: The efficacy in reversing deep neuromuscular block was the same between 4 mg kg⁻¹ sugammadex and adamgammadex. However, in the lowest dose groups of 2 and 4 mg kg⁻¹ adamgammadex, adequate reversal could not be achieved in all subjects. The recovery time of TOF ratio to 0.9, 0.8, and 0.7 was shorter in the adamgammadex 10 mg kg⁻¹ group than in the sugammadex 4 mg kg⁻¹ group. The average values of the TOF ratio after 3 min of administration of adamgammadex 8 and 10 mg kg⁻¹ and sugammadex 4 mg kg⁻¹ were >90%. There were no serious adverse events after the use of adamgammadex, and no subjects had to be withdrawn from the trial.

Conclusions: Adamgammadex enabled quick, predictable, and tolerable reversion of rocuronium-induced deep neuromuscular block in a dose-dependent manner. Adamgammadex doses of 6–10 mg kg⁻¹ might be the recommended dose range for further exploration of efficacy. Clinical Trial Registration: This study was registered at chictr.org.cn, identifier: ChiCTR2000038391.

Carboxymethyl-γ-cyclodextrin, a novel selective relaxant binding agent for the reversal of neuromuscular block induced by aminosteroid neuromuscular blockers: an ex vivo laboratory study

BACKGROUND

Residual neuromuscular block at the end of surgery may compromise the patient's safety. The risk of airway complications can be minimized through monitoring of neuromuscular function and reversal of neuromuscular block if needed. Effective reversal can be achieved with selective relaxant binding agents, however, sugammadex is the only clinically approved drug in this group. We investigated the concentration-response properties of a novel selective relaxant binding agent, carboxymethyl-γ-cyclodextrin for the reversal of neuromuscular block. We evaluated the hypothesis that it is equally potent for reversing neuromuscular block as sugammadex.

METHODS

Phrenic nerve - hemidiaphragm tissue preparations were isolated from male Wistar rats and suspended in a tissue holder allowing electrical stimulation of the nerve and monitoring of muscle contraction force. Concentration-response relationships were constructed for the neuromuscular blocking agents rocuronium, pipecuronium, and vecuronium. The half-effective concentrations of sugammadex and carboxymethyl-γ-cyclodextrin for reversal of neuromuscular block were determined.

RESULTS

The half effective concentrations (95% confidence interval, CI) were 7.50 (6.93-8.12) μM for rocuronium, 1.38 (1.33-1.42) μM for pipecuronium, and 3.69 (3.59-3.80) μM for vecuronium. The half effective concentrations (95% CI) of carboxymethyl-γ-cyclodextrin and sugammadex were 35.89 (32.67-39.41) μM and 3.67 (3.43-3.92) μM, respectively, for the reversal of rocuronium-induced block; 10.14 (9.61-10.70) μM and 0.67 (0.62-0.74) μM, respectively, for the reversal of pipecuronium-induced block; and 376.1 (341.9-413.8) μM and 1.45 (1.35-1.56) μM, respectively, for the reversal of vecuronium-induced block.

CONCLUSIONS

Carboxymethyl-γ-cyclodextrin is an effective, but less potent agent for reversal of neuromuscular block than sugammadex.

MRGPRX2 activation in mast cells by neuromuscular blocking agents and other agonists: Modulation by sugammadex

BACKGROUND

Neuromuscular-blocking agents (NMBAs) can cause both IgE-dependent and IgE-independent anaphylactic reactions, with activation of the mast cell receptor MRGPRX2 being important to the latter. Sugammadex, a reversal agent for certain aminosteroid NMBAs, has been proposed as an antidote for these anaphylactic events with conflicting outcomes.

OBJECTIVE

We further characterize the involvement of MRGPRX2 in NMBA-induced mast cell activation and determine how this is influenced by sugammadex. We then apply these in vitro results to infer the possible utility of sugammadex in the acute management of non-IgE-dependent anaphylaxis.

METHODS

The LAD2 human mast cell line and a MRGPRX2 knock-down derivative were used to validate the involvement of MRGPRX2 and to test the effect of sugammadex on mast cell activation by NMBAs and other MRGPRX2 agonists.

RESULTS

All MRGPRX2 agonists tested were shown to induce MRGPRX2-dependent LAD2 mast cell calcium mobilization and cytokine release and all, apart from rocuronium, induced degranulation. Co-treatment of mast cells with sugammadex and some MRGPRX2 agonists significantly reduced cell activation, but if sugammadex was administered a few minutes following stimulation, degranulation was not attenuated. However, addition of sugammadex up to 180 min following LAD2 MRGPRX2 stimulation, significantly reduced CCL2 mRNA and protein induction.

CONCLUSIONS AND CLINICAL RELEVANCE

We show that sugammadex, known to reverse muscle blockade by certain NMBAs, is also able to reduce MRGPRX2 activation by NMBAs and other, but not all, MRGPRX2 agonists. As sugammadex was ineffective in attenuating mast cell degranulation when added rapidly post MRGPRX2 activation, this suggests against the agent having efficacy in controlling acute symptoms of anaphylaxis to NMBAs caused by MRGPRX2 activation. Interestingly, however, sugammadex did impair MRGPRX2-induced CCL2 release, suggesting that it may have some benefit in perhaps dampening less well-defined adverse effects of MRGPRX2-dependent anaphylaxis associated with the more slowly elaborated mast cell mediators.

Use of sugammadex in patients with neuromuscular disorders: a systematic review of case reports

Background

Sugammadex is a modified gamma-cyclodextrin that acts by selectively encapsulating free amino-steroidal neuromuscular relaxants. Several case reports have been published on the use of sugammadex in patients with neuromuscular disorders that include neuromuscular junction diseases, myopathies, neuropathies, and motor neurone disorders. The primary aim of this review is to systematically review the evidence on the use of sugammadex in patients with this heterogeneous group of diseases and provide recommendations for clinical practice.

Methods

A systematic electronic search of Medline, Embase and CINAHL databases was done until June 2019, to identify case reports describing the use of sugammadex in adult surgical patients with neuromuscular disorders.

Results

Of the 578 records identified through database searches, 43 articles were finally included for the systematic review. Of these, 17 reports were on patients with myopathy, 15 reports on myasthenia gravis, 9 reports on motor neuron diseases and 2 reports on neuropathies.

Conclusions

Majority of the articles reviewed report successful use of sugammadex to reverse steroidal muscle relaxants, especially rocuronium, in patients with neuromuscular diseases. However, with sugammadex, unpredictability in response and uncertainty regarding optimum dose still remain issues. Quantitative neuromuscular monitoring to ensure complete reversal and adequate postoperative monitoring is strongly recommended in these patients, despite the use of sugammadex.

Is lower-dose sugammadex a cost-saving strategy for reversal of deep neuromuscular block? Facts and fiction

BACKGROUND

Sugammadex, a γ-cyclodextrin derivative, belongs to a new class of selective relaxant binding agents. Sugammadex was approved 10-years ago by the European medicines agency and today is used in clinical anesthesia and emergency medicine globally. In this review, indications for neuromuscular block, the challenge of neuromuscular monitoring and the practice of under-dosing of sugammadex as a potential cost-saving strategy are discussed.

MAIN BODY

Reversal of neuromuscular block is important to accelerate the spontaneous recovery of neuromuscular function. Sugammadex is able to reverse a rocuronium- or vecuronium-induced neuromuscular block rapidly and efficiently from every depth of neuromuscular block. However, since sugammadex was introduced in clinical anesthesia, several studies have reported administration of a lower-than-recommended dose of sugammadex. The decision to under-dose sugammadex is often motivated by cost reduction concerns, as the price of sugammadex is much higher than that of neostigmine outside the United States. However, under-dosing of sugammadex leads to an increased risk of recurrence of neuromuscular block after an initial successful (but transient) reversal. Similarly, when not using objective neuromuscular monitoring, under-dosing of sugammadex may result in residual neuromuscular block in the postoperative care unit, with its attendant negative pulmonary outcomes. Therefore, an appropriate dose of sugammadex, based on objective determination of the depth of neuromuscular block, should be administered to avoid residual or recurrent neuromuscular block and attendant postoperative complications. Whether the reduction in perioperative recovery time of the patient can be translated into additional procedural cases performed, faster operative turnover times, or improved organizational resource utilization, has yet to be determined in actual clinical practice that includes verification of neuromuscular recovery prior to tracheal extubation.

CONCLUSIONS

The current review addresses the indications for neuromuscular block, the challenge of neuromuscular monitoring, the practice of under-dosing of sugammadex as a potential cost-saving strategy in reversal of deep neuromuscular block, the economics of sugammadex administration and the potential healthcare cost-saving strategies.

Preparing for the unexpected: special considerations and complications after sugammadex administration

Sugammadex, a modified gamma-cyclodextrin, has changed clinical practice of neuromuscular reversal dramatically. With the introduction of this selective relaxant binding agent, rapid and reliable neuromuscular reversal from any depth of block became possible. Sugammadex can reverse neuromuscular blockade without the muscarinic side effects typically associated with the administration of acetylcholinesterase inhibitors. However, what remained unchanged is the incidence of residual neuromuscular blockade. It is known that sugammadex cannot always prevent its occurrence, if appropriate dosing is not chosen based on the level of neuromuscular paralysis prior to administration determined by objective neuromuscular monitoring. Alternatively, excessive doses of sugammadex administered in an attempt to ensure full and sustained reversal may affect the effectiveness of rocuronium in case of immediate reoperation or reintubation. In such emergent scenarios that require onset of rapid and reliable neuromuscular blockade, the summary of product characteristics (package insert) recommends using benzylisoquinolinium neuromuscular blocking agents or a depolarizing agent. However, if rapid intubation is required, succinylcholine has a significant number of side effects, and benzylisoquinolinium agents may not have the rapid onset required. Therefore, prior administration of sugammadex introduces a new set of potential problems that require new solutions. This novel reversal agent thus presents new challenges and anesthesiologists must familiarize themselves with specific issues with its use (e.g., bleeding risk, hypermagnesemia, hypothermia). This review will address sugammadex administration in such special clinical situations.

Current Status of Neuromuscular Reversal and Monitoring

Postoperative residual neuromuscular block has been recognized as a potential problem for decades, and it remains so today. Traditional pharmacologic antagonists (anticholinesterases) are ineffective in reversing profound and deep levels of neuromuscular block; at the opposite end of the recovery curve close to full recovery, anticholinesterases may induce paradoxical muscle weakness. The new selective relaxant-binding agent sugammadex can reverse any depth of block from aminosteroid (but not benzylisoquinolinium) relaxants; however, the effective dose to be administered should be chosen based on objective monitoring of the depth of neuromuscular block.

To guide appropriate perioperative management, neuromuscular function assessment with a peripheral nerve stimulator is mandatory. Although in many settings, subjective (visual and tactile) evaluation of muscle responses is used, such evaluation has had limited success in preventing the occurrence of residual paralysis. Clinical evaluations of return of muscle strength (head lift and grip strength) or respiratory parameters (tidal volume and vital capacity) are equally insensitive at detecting neuromuscular weakness. Objective measurement (a train-of-four ratio greater than 0.90) is the only method to determine appropriate timing of tracheal extubation and ensure normal muscle function and patient safety.

The presumed central nervous system effects of rocuronium in a neonate and its reversal with sugammadex

We describe a 2-day-old male infant who received rocuronium as part of general anesthesia for a tracheal esophageal fistula repair. Postoperatively, he had prolonged central and peripheral neuromuscular blockade despite cessation of the rocuronium infusion several hours previously. This case discusses the presumed central nervous system effects of rocuronium in a neonate and its effective reversal with sugammadex.

Synthesis of uniform cyclodextrin thioethers to transport hydrophobic drugs

Methyl and ethyl thioether groups were introduced at all primary positions of α-, β-, and γ-cyclodextrin by nucleophilic displacement reactions starting from the corresponding per-(6-deoxy-6-bromo)cyclodextrins. Further modification of all 2-OH positions by etherification with iodo terminated triethylene glycol monomethyl ether (and tetraethylene glycol monomethyl ether, respectively) furnished water-soluble hosts. Especially the β-cyclodextrin derivatives exhibit very high binding potentials towards the anaesthetic drugs sevoflurane and halothane. Since the resulting inclusion compounds are highly soluble in water at temperatures ≤37 °C they are good candidates for new aqueous dosage forms which would avoid inhalation anaesthesia.

Safety and Efficacy of Sugammadex for Neuromuscular Blockade Reversal

Since its first human use in 2005, the γ-cyclodextrin sugammadex (Org 25969) has had the potential to become the reversal agent of choice, for rocuronium- or vecuronium-induced neuromuscular blockade. Sugammadex binds to the aminosteroid neuromuscular blocker, encapsulating it and extracting it from the neuromuscular junction, effectively ceasing activity and allowing neuromuscular transmission to recover rapidly. Phases I–III and subsequent trials have found sugammadex to be safe and effective in a wide range of doses and for the reversal of a range of depth of muscle relaxation in healthy volunteers and a variety of disease states. Sugammadex use may allow refinement of anesthetic practice and improvement in surgical conditions, through the maintenance of deep neuromuscular blockade right to the end of surgery, with subsequent rapid reversal. Debate remains about the use of sugammadex in the treatment of rocuronium anaphylaxis and airway emergencies. The high price of sugammadex currently prohibits its routine use, but if the price falls, after expiry of its patent, it may become cost-effective as a readily available agent in certain specific clinical situations. Serious adverse reactions have occurred in less than 1% of patients and are most commonly because of hypersensitivity. No deaths have been reported, but caution is advised in neonates, pediatrics, and pregnancy where data are lacking.

Reversal of profound rocuronium or vecuronium-induced neuromuscular block with sugammadex in isoflurane-anaesthetised dogs

This study evaluated the use of sugammadex for reversal of profound neuromuscular blockade induced with rocuronium or vecuronium in dogs. Anaesthesia was induced and maintained with isoflurane in oxygen in eight dogs on two occasions. Neuromuscular blockade was monitored using peroneal nerve stimulation and acceleromyography. Rocuronium 0.6 mg/kg or vecuronium 0.1mg/kg was administered intravenously (IV), followed 5 min later by sugammadex 8 mg/kg IV. Lag and onset time of rocuronium and vecuronium, lag time from sugammadex injection to recovery of first twitch response, recovery of T1/T0 to 25% and 75%, recovery index, and time to recovery of the train-of-four ratio (T4/T1) to 0.9 were recorded. Cardiovascular and respiratory parameters were also noted. Statistical analysis was performed using one-way ANOVA. Onset time for rocuronium (37 ± 18s; [mean ± SD]) was significantly shorter than for vecuronium (62 ± 15s) (P<0.04). No other significant differences were found between the two groups. After both rocuronium and vecuronium blockade, T4/T1 recovered to 0.9 in under 2 min after sugammadex (58.1 ± 67.8s and 98.1 ± 70.3s, respectively; P<0.32). Sugammadex can reverse profound neuromuscular blockade induced by vecuronium or rocuronium safely and rapidly in isoflurane-anaesthetised dogs.

Drug-specific cyclodextrins with emphasis on sugammadex, the neuromuscular blocker rocuronium and perioperative anaphylaxis: implications for drug allergy

Cyclodextrins, oligosaccharides linked in a circular arrangement around a central cavity, are used extensively in the pharmaceutical industry to improve drug delivery. Their usefulness depends on their capacity to form a drug inclusion, or host-guest, complex within the cavity. In an attempt to improve the delivery of the widely used neuromuscular blocking drug (NMBD) rocuronium, a rocuronium inclusion complex was formed with a chemically modified γ-cyclodextrin. The high binding affinity and specificity of the modified carrier (named sugammadex) for rocuronium (and other aminosteroid NMBDs) led to its use in anaesthesia as an innovative and useful agent for rapid reversal of rocuronium-induced neuromuscular block by sequestering the drug as an inclusion complex. This, in turn, led to the suggestion that sugammadex might be useful to remove the NMBD from the circulation of patients experiencing rocuronium-induced anaphylaxis, a suggestion subsequently supported in case reports where traditional treatment had failed. Successful resuscitations suggested that sugammadex might be a valuable new treatment for such intractable cases but, given the inappropriateness of clinical trials, confirmation or refutation will have to await the slow accumulation of results of individual case reports. Important questions related to antibody accessibility of drug allergenic structures on the rocuronium-sugammadex inclusion complex, and the competition between sugammadex and IgE antibodies (both free and cell bound) for rocuronium, also remain and can be investigated in vitro. The sugammadex findings indicate that the use of carrier molecules such as the cyclodextrins to improve drug delivery will sometimes give rise to changed immunologic and allergenic behaviour of some drugs and this will have to be taken into account in preclinical drug safety assessments of drug-carrier complexes. The possibility of encapsulating and removing other allergenic drugs, e.g., penicillins and cephalosporins, in cases of difficult-to-reverse anaphylaxis to these drugs is discussed.

Equipment to manage a difficult airway during anaesthesia

Airway complications are a leading cause of morbidity and mortality in anaesthesia. Effective management of a difficult airway requires the timely availability of suitable airway equipment. The Australian and New Zealand College of Anaesthetists has recently developed guidelines for the minimum set of equipment needed for the effective management of an unexpected difficult airway (TG4 [2010] www.anzca.edu.au/resources/professionaldocuments). TG4 [2010] is based on expert consensus, underpinned by wide consultation and an extensive review of the available evidence, which is summarised in a Background Paper (TG4 BP [2010] www.anzca.edu.au/ resources/professional-documents). TG4 [2010] will be reviewed at the end of one year and thereafter every five years or more frequently if necessary. The current paper is reproduced directly from the Background Paper (TG4 BP [2010]).

Sugammadex reverses neuromuscular block induced by 3-desacetyl-vecuronium, an active metabolite of vecuronium, in the anaesthetised rhesus monkey

BACKGROUND AND OBJECTIVE

3-Desacetyl-vecuronium is an active metabolite of the neuromuscular blocking agent (NMBA) vecuronium, which might lead to residual paralysis after prolonged administration of vecuronium in critically ill patients with renal failure. This study investigated the ability of sugammadex to reverse 3-desacetyl-vecuronium-induced neuromuscular block (NMB) in the anaesthetised rhesus monkey.

METHODS

Experiments were performed in anaesthetised female rhesus monkeys. After bolus intravenous injection of vecuronium (n = 8) or 3-desacetyl-vecuronium (n = 8) 10 μg kg(-1) (ED90), a continuous infusion of the same NMBA was started to maintain the first twitch of the train-of-four (TOF) at 10% of baseline value. The infusion was stopped and NMB recovered spontaneously. The procedure was repeated, but immediately after stopping the infusion, an intravenous bolus dose of sugammadex 0.5 or 1.0 mg kg(-1) was given. For each NMBA, four placebo experiments were performed, in which the second recovery from NMB was also spontaneous. For all experiments, time to recovery of the TOF ratio to 90% was retrieved.

RESULTS

After administration of sugammadex for reversal of 3-desacetyl-vecuronium-induced NMB, recovery was significantly faster than spontaneous recovery. Mean time to recovery of TOF to 90% was 3.2 min (sugammadex 0.5 mg kg(-1)) and 2.6 min (1.0 mg kg(-1)), compared to spontaneous recovery (17.6 min). For vecuronium-induced NMB, mean time to recovery of TOF to 90% was 17.1 min (0.5 mg kg(-1)) and 4.6 min (1.0 mg kg(-1)), compared to spontaneous recovery (23.4 min).

CONCLUSION

Sugammadex rapidly and effectively reversed 3-desacetyl-vecuronium-induced NMB in the rhesus monkey, at a lower dose than that needed to reverse vecuronium-induced NMB.

Sugammadex: a selective relaxant-binding agent providing rapid reversal

PURPOSE OF REVIEW

Sugammadex is a new reversal agent with a unique mechanism of action in anaesthesia. Because of its rapid onset of action and its efficacy in determining neuromuscular blockade at any time, it opens up new perspectives in anaesthesia.

RECENT FINDINGS

During the last few years, a lot of phase II and III studies have been published, investigating various groups of patients and clinical situations. Sugammadex has been shown to be a well tolerated drug, which appears to meet every challenge it is presented with in daily clinical practice.

SUMMARY

Sugammadex binds amino-steroidal muscle relaxants by encapsulation. It enables rapid reversal of neuromuscular blockade at any time point and at any depth of block. Its effects are predictable and very reliable, in contrast to cholinesterase inhibitors. This opens up new perspectives in anaesthesia. Even an emergency reversal of high-dose rocuronium-induced neuromuscular blockade is possible with sugammadex and times to full recovery (TOF 0.9) are faster than after spontaneous recovery from suxamethonium.

Residual neuromuscular block: lessons unlearned. Part II: methods to reduce the risk of residual weakness

The aim of the second part of this review is to examine optimal neuromuscular management strategies that can be used by clinicians to reduce the risk of residual paralysis in the early postoperative period. Current evidence has demonstrated that frequently used clinical tests of neuromuscular function (such as head lift or hand grip) cannot reliably exclude the presence of residual paralysis. When qualitative (visual or tactile) neuromuscular monitoring is used (train-of-four [TOF], double-burst, or tetanic stimulation patterns), clinicians often are unable to detect fade when TOF ratios are between 0.6 and 1.0. Furthermore, the effect of qualitative monitoring on postoperative residual paralysis remains controversial. In contrast, there is strong evidence that acceleromyography (quantitative) monitoring improves detection of small degrees (TOF ratios >0.6) of residual blockade. The use of intermediate-acting neuromuscular blocking drugs (NMBDs) can reduce, but do not eliminate, the risk of residual paralysis when compared with long-acting NMBDs. In addition, complete recovery of neuromuscular function is more likely when anticholinesterases are administered early (>15-20 minutes before tracheal extubation) and at a shallower depth of block (TOF count of 4). Finally, the recent development of rapid-onset, short-acting NMBDs and selective neuromuscular reversal drugs that can effectively antagonize deep levels of blockade may provide clinicians with novel pharmacologic approaches for the prevention of postoperative residual weakness and its associated complications.

[Sugammadex, a novel drug for neuromuscular blockade reversal]

Significant progress in the management of aminosteroid nondepolarizing neuromuscular blockers will follow the introduction of sugammadex (Org 25969). Safety and rapid recovery of muscle force will improve and the adverse effects of acetylcholinesterase inhibitors will be avoided. Sugammadex is a modified gamma-cyclodextrin agent developed for the specific reversal of rocuronium and, to a lesser extent, vecuronium. This novel drug functions by means of encapsulation (chelation). Sugammadex was recently approved by the European Medicines Evaluation Agency and became available in Spain in 2009, leading to a series of changes related to patient safety and surgical conditions. We review the literature on sugammadex published to date.

Incidence of Residual Neuromuscular Blockade in a Post-Anaesthetic Care Unit

We conducted a prospective observational study to assess the incidence of residual neuromuscular blockade (RNMB) in a post-anaesthetic care unit (PACU) of a tertiary hospital. The subjects were 102 patients undergoing general anaesthesia with neuromuscular blockade (NMB). The procedural anaesthetists were unaware of their patients’ inclusion in the study, and the choice of muscle relaxant and use of reversal agents were at the anaesthetists’ discretion. On arrival to the PACU, the train-of-four ratio was assessed using electromyography, repeated every five minutes until the train-of-four ratio exceeded 0.9. RNMB was defined as a train-of-four ratio < 0.9. The requirement for airway support, incidence of desaturation while in the PACU and time to eligibility for PACU discharge were recorded. The mean interval between the last dose of relaxant and arrival in the PACU for patients with RNMB was 81 minutes. An intermediate-acting muscle relaxant had been used for most patients. Despite this, RNMB was observed in 31% (95% confidence interval 25 to 47%) of patients. Our findings suggest that RNMB in the PACU is common. As RNMB may predispose to postoperative complications, anaesthetists should utilise quantitative monitoring to assess neuromuscular blockade and optimise reversal use. Anaesthetists should be aware that intervals between the last dose of relaxant of well over one hour do not exclude the possibility of RNMB, even when using intermediate-acting neuromuscular blockade agents.

Preclinical pharmacology of sugammadex

Since the introduction of nondepolarizing neuromuscular blocking agents, acetylcholinesterase inhibitors have been used to increase the speed of recovery from neuromuscular blockade. The major disadvantages of acetylcholinesterase inhibitors are their lack of activity against profound neuromuscular blockade and their activity outside the neuromuscular junction resulting in unwanted side effects, requiring cotreatment with a muscarinic antagonist. An alternative to acetylcholinesterase inhibitors is the encapsulating agent sugammadex. This agent has been specifically designed to encapsulate the steroidal neuromuscular blocking agents rocuronium and vecuronium. This review describes the effects of sugammadex in in vitro tissue and in vivo animal experiments. The encapsulation approach allows reversal of any degree of neuromuscular blockade because the dose of sugammadex can be adjusted to encapsulate sufficient neuromuscular blocking molecules to cause effective reversal. Because this interaction is a drug-drug interaction, reversal can be achieved very fast but is limited by the circulation time. Sugammadex is also effective against neuromuscular blockade under conditions with reduced acetylcholine release, which potentiate the action of neuromuscular blocking agents. Sugammadex does not cause cholinergic side effects, preventing the need of coadministration of muscarinic antagonists. Because of these properties, sugammadex has the potential to become a very useful drug for the management of neuromuscular blockade.

Neostigmine but not sugammadex impairs upper airway dilator muscle activity and breathing

BACKGROUND

Cholinesterase inhibitor-based reversal agents, given in the absence of neuromuscular block, evoke a partial upper airway obstruction by decreasing skeletal upper airway muscle function. Sugammadex reverses neuromuscular block by encapsulating rocuronium. However, its effects on upper airway integrity and breathing are unknown.

METHODS

Fifty-one adult male rats were anaesthetized with isoflurane, tracheostomized, and a femoral artery and vein were cannulated. First, we compared the efficacy of sugammadex 15 mg kg(-1) and neostigmine 0.06 mg kg(-1) to reverse respiratory effects of rocuronium-induced partial paralysis [train-of-four ratio (T4/T1)=0.5]. Subsequently, we compared the safety of sugammadex and neostigmine given after recovery of the T4/T1 to 1, by measuring phasic genioglossus activity and breathing.

RESULTS

During partial paralysis (T4/T1=0.5), time to recovery of minute volume to baseline values was 10.9 (2), 75.8 (18), and 153 (54) s with sugammadex, neostigmine, and placebo, respectively (sugammadex was significantly faster than neostigmine and placebo, P<0.05). Recovery of T4/T1 was also faster for sugammadex than neostigmine and placebo. Neostigmine administration after complete recovery of T4/T1 decreased upper airway dilator muscle activity to 64 (30)% of baseline and decreased tidal volume (P<0.05 for both variables), whereas sugammadex had no effect on either variable.

CONCLUSIONS

In contrast to neostigmine, which significantly impairs upper airway dilator muscle activity when given after recovery from neuromuscular block, a reversal dose of sugammadex given under the same conditions does not affect genioglossus muscle activity and normal breathing. Human studies will be required to evaluate the clinical relevance of our findings.