Development and potential clinical impairment of ultra-short-acting neuromuscular blocking agents

Coadministration of intravenous calcium along with neostigmine for rapid neuromuscular blockade recovery: A systematic review and meta-analysis

Postoperative residual curarization (PORC) and the impact of the coadministration of intravenous calcium along with an acetylcholinesterase inhibitor on it are not well addressed. Extensive electronic database screening was done until October 7, 2022 after enlisting the protocol of this systematic review in PROSPERO (CRD42021274879). Randomized controlled trials (RCTs) evaluating the impact of intravenous calcium and neostigmine coadministration on neuromuscular recovery were included in this meta-analysis. Our search retrieved four RCTs with a total of 266 patients. The application of calcium shortened the neuromuscular recovery time (SMD = -2.13, 95% confidence interval [CI]: -2.66 to -1.59, I2 = 66%) and reduced the risk of PORC at 5 min (odds ratio [OR] = 0.21, 95% CI: 0.10-0.46, I2 = 0%), with an improved train-of-four (TOF) ratio at 5 min (mean difference [MD] = 9.28, 95% CI: 4-14.57, I2 = 66%). However, neither significant reduction in PORC at 10 min (OR = 0.41, 95% CI: 0.15-1.09, I2 = 0%) nor a better TOF ratio was associated with coadministration of calcium (MD = 0.40, 95% CI: -1.3-2.11). Coadministration of calcium along with neostigmine during the early period of neuromuscular blockade reversal can be used to enhance neuromuscular recovery.

Comparison of neuromuscular blockade recovery co-administered with neostigmine and different doses of calcium gluconate: a randomized control trial

BACKGROUND

Calcium increases the probability of transmitter release at the neuromuscular junction. It is not known whether there is a dose-dependent relationship between the dosage of calcium gluconate and the probability of transmitter release for non-depolarizing neuromuscular blockade (NMB) recovery by acetylcholinesterase inhibitors (AchEIs). This study compared the neuromuscular recovery time and the incidence of postoperative residual curarization (PORC) according to the dosage of calcium gluconate co-administered with neostigmine in three patient groups.

METHODS

Patients were randomly allocated to a control group, a 5 mg/kg calcium gluconate group (calcium 5 group), or a 10 mg/kg calcium gluconate group (calcium 10 group). In patients with a TOF ratio (TOFr) between 0.2-0.7, 0.04 mg/kg of neostigmine was administered and both 0.2 mg of glycopyrrolate and 0.4 mg of atropine per 1 mg of neostigmine were administered. And additional 5 or 10 mg/kg of calcium gluconate were administrated to the calcium 5 and 10 groups. The primary endpoint was neuromuscular recovery time (the time between reversal and TOFr≥0.9). The secondary endpoints were the incidence of PORC at 5, 10, and 20 min after reversal administration and the train-of-four ratio (TOFr) at each time point.

RESULTS

The neuromuscular recovery time was 5.3 min in the control group, 3.9 min in the calcium 5 group, and 4.1 min in the calcium 10 group, respectively (P = 0.004). The incidence of PORC at 5 min after neostigmine administration was 12 in the control group, 4 in the calcium 5 group, and 4 in the calcium 10 group, respectively, with statistical significance (P = 0.014).

CONCLUSIONS

The co-administration of calcium gluconate with neostigmine safely promoted early NMB recovery, and the neuromuscular recovery time of the calcium 10 group tended to be more evenly distributed than that of the calcium 5 group.

TRIAL REGISTRATION

https://cris.nih.go.kr/cris/index.jsp(KCT0004182 ). Date of registration: August 122,019.

Supramolecular therapeutics to treat the side effects induced by a depolarizing neuromuscular blocking agent

Succinylcholine (Sch) is the only depolarizing neuromuscular blocking agent widely used for rapid sequence induction in emergency rooms. Unfortunately, a variety of (sometimes lethal) adverse effects, such as hyperkalemia and cardiac arrest, are associated with its use, and currently there are no specific antidotes to reverse Sch or to treat these side-effects. Methods: The binding behaviors of Sch and several synthetic receptors, including cucurbit[7]uril, sulfo-calix[4]arene and water-soluble carboxylatopillar[6]arene (WP[6]), were first investigated. With a mouse model, a leathal dose of Sch was selected for evaluation of the antidotal effects of these synthetic receptors on Sch induced mortality. The antidotal effects of a selected synthetic receptor, WP[6], on Sch induced cardiac arrhythmias, hyperkalemia, rhabdomyolysis and paralysis were subsequently evaluated with rat and mouse models. The reversal mechanism was also investigated at a cellular level. Results: All of these macrocyclic molecules exhibited relatively high binding affinities with Sch in vitro. In a Sch-overdosed mouse model, immediate injection of these synthetic receptors right after Sch administration increased the overall survival rate, with WP[6] standing out with the most effective antidotal effects. In addition, administration of WP[6] also reversed the paralysis induced by Sch in a mouse model. Moreover, infusion of WP[6] to Sch-overdosed rats reduced the incidence of cardiac arrhythmia, inhibited the otherwise abnormally high serum potassium levels, and relieved the muscular damage. At the cellular level, WP[6] reversed the Sch induced depolarization and reduced the efflux of intracellular potassium. Conclusion: Synthetic receptors, particularly WP[6], exhibited high binding affinities towards Sch, and presented a significant potential as supramolecular therapeutics to treat the various side effects of Sch by specifically sequestering Sch in vivo.

Effects of calcium chloride coadministered with neostigmine on neuromuscular blockade recovery: A double-blind randomised study

BACKGROUND

Ionised calcium plays an important role in neuromuscular transmission, but its effects on the reversal of nondepolarising neuromuscular blockade have not been fully evaluated.

OBJECTIVE

We examined whether calcium chloride coadministered with neostigmine could enhance the rate of neuromuscular recovery.

DESIGN

Randomised double-blind trial.

SETTING

A tertiary teaching hospital.

PATIENTS

In total, 53 patients undergoing elective surgery under general anaesthesia with neuromuscular monitoring by acceleromyography using a TOF-Watch SX monitor.

INTERVENTIONS

Patients were randomly allocated to receive either 5 mg kg of calcium chloride (calcium group, n = 26) or the same volume of normal saline (control group, n = 27) coadministered with 25 μg kg of neostigmine and 15 μg kg of atropine at the end of surgery.

MAIN OUTCOME MEASURES

The primary end point was the neuromuscular recovery time [time from neostigmine administration to recovery of the TOF ratio (TOFr) to 0.9]. Secondary end points included the TOFr at 5, 10 and 20 min after neostigmine administration and the incidence of postoperative residual curarisation (PORC), defined as a TOFr less than 0.9 at each time point.

RESULTS

The neuromuscular recovery time was significantly faster in the calcium group than in the control group (median [Q1 to Q3]; 5.0 [3.0 to 7.0] vs. 6.7 [5.7 to 10.0] min, respectively; P = 0.007). At 5 min after neostigmine administration, the TOFr was higher [87 (74 to 100) vs. 68 (51 to 81)%, respectively; P = 0.002] and the incidence of PORC was lower (50.0 vs. 81.5%, respectively; P = 0.016) in the calcium group than in the control group. There were no differences between the two groups with respect to the TOFr or incidence of PORC at 10 and 20 min after neostigmine administration.

CONCLUSION

Calcium chloride coadministered with neostigmine enhanced neuromuscular recovery in the early period of nondepolarising neuromuscular blockade reversal.

Curare alkaloids from Matis Dart Poison: Comparison with d-tubocurarine in interactions with nicotinic, 5-HT3 serotonin and GABAA receptors

Several novel bisbenzylisoquinoline alkaloids (BBIQAs) have recently been isolated from a Matis tribe arrow poison and shown by two-electrode voltage-clamp to inhibit mouse muscle nicotinic acetylcholine receptors (nAChR). Here, using radioligand assay with Aplysia californica AChBP and radioiodinated α-bungarotoxin ([125I]-αBgt), we show that BBIQA1, BBIQA2, and d-tubocurarine (d-TC) have similar affinities to nAChR orthosteric site. However, a competition with [125I]-αBgt for binding to the Torpedo californica muscle-type nAChR revealed that BBIQAs1, 2, and 3 are less potent (IC50s = 26.3, 8.75, and 17.0 μM) than d-TC (IC50 = 0.39 μM), while with α7 nAChR in GH4C1 cells, BBIQA1 was less potent that d-TC (IC50s = 162 μM and 7.77 μM, respectively), but BBIQA2 was similar (IC50 = 5.52 μM). In inhibiting the Ca2+ responses induced by acetylcholine in Neuro2a cells expressing the mouse adult α1β1εδ nAChR or human α7 nAChR, BBIQAs1 and 2 had similar potencies to d-TC (IC50s in the range 0.75-3.08 μM). Our data suggest that BBIQA1 and BBIQA2 can inhibit adult muscle α1β1εδ nAChR by both competitive and noncompetitive mechanisms. Further experiments on neuronal α3β2, α4β2, and α9α10 nAChRs, expressed in Xenopus laevis oocytes, showed that similar potencies for BBIQAs1, 2, and d-TC. With α3β2γ2 GABAAR currents were almost completely inhibited by d-TC at a high (100 μM) concentration, but BBIQAs1 and 2 were less potent (only 40-50% inhibition), whereas in competition with Alexa Fluor 546-α-cobratoxin for binding to α1β3γ2 GABAAR in Neuro2a cells, d-TC and these analogs had comparable affinities. Especially interesting effects of BBIQAs1 and 2 in comparison with d-TC were observed for 5-HT3AR: BBIQA1 and BBIQA2 were 5- and 87-fold less potent than d-TC (IC50 = 22.63 nM). Thus, our results reveal that these BBIQAs differ from d-TC in their potencies towards certain Cys-loop receptors, and we suggest that understanding the reasons behind this might be useful for future drug design.

Factors that affect the onset of action of non-depolarizing neuromuscular blocking agents

Neuromuscular blockade plays an important role in the safe management of patient airways, surgical field improvement, and respiratory care. Rapid-sequence induction of anesthesia is indispensable to emergency surgery and obstetric anesthesia, and its purpose is to obtain a stable airway, adequate depth of anesthesia, and appropriate respiration within a short period of time without causing irritation or damage to the patient. There has been a continued search for new neuromuscular blocking drugs (NMBDs) with a rapid onset of action. Factors that affect the onset time include the potency of the NMBDs, the rate of NMBDs reaching the effect site, the onset time by dose control, metabolism and elimination of NMBDs, buffered diffusion to the effect site, nicotinic acetylcholine receptor subunit affinity, drugs that affect acetylcholine (ACh) production and release at the neuromuscular junction, drugs that inhibit plasma cholinesterase, presynaptic receptors responsible for ACh release at the neuromuscular junction, anesthetics or drugs that affect muscle contractility, site and methods for monitoring neuromuscular function, individual variability, and coexisting disease. NMBDs with rapid onset without major adverse events are expected in the next few years, and the development of lower potency NMBDs will continue. Anesthesiologists should be aware of the use of NMBDs in the management of anesthesia. The choice of NMBD and determination of the appropriate dosage to modulate neuromuscular blockade characteristics such as onset time and duration of neuromuscular blockade should be considered along with factors that affect the effects of the NMBDs. In this review, we discuss the factors that affect the onset time of NMBDs.

Neuronal Effects of Sugammadex in combination with Rocuronium or Vecuronium

Rocuronium (ROC) and Vecuronium (VEC) are the most currently used steroidal non-depolarizing neuromuscular blocking (MNB) agents. Sugammadex (SUG) rapidly reverses steroidal NMB agents after anaesthesia. The present study was conducted in order to evaluate neuronal effects of SUG alone and in combination with both ROC and VEC. Using MTT, CASP-3 activity and Western-blot we determined the toxicity of SUG, ROC or VEC in neurons in primary culture. SUG induces apoptosis/necrosis in neurons in primary culture and increases cytochrome C (CytC), apoptosis-inducing factor (AIF), Smac/Diablo and Caspase 3 (CASP-3) protein expression. Our results also demonstrated that both ROC and VEC prevent these SUG effects. The protective role of both ROC and VEC could be explained by the fact that SUG encapsulates NMB drugs. In BBB impaired conditions it would be desirable to control SUG doses to prevent the excess of free SUG in plasma that may induce neuronal damage. A balance between SUG, ROC or VEC would be necessary to prevent the risk of cell damage.

Novel neuromuscular blocking drugs and antagonists

PURPOSE OF REVIEW

This review summarizes recent progress in the development of new muscle relaxants that are inactivated by cysteine, and considers the evolving paradigm of selective relaxant binding or degrading agents that can reverse neuromuscular blockade at any time.

RECENT FINDINGS

The benzylisoquinoline compound gantacurium is a nondepolarizing muscle relaxant with an ultrashort duration largely determined by the rapid rate at which endogenous L-cysteine binds to, and permanently inactivates, the molecule. Although the clinical development of gantacurium has been hampered by modest histamine release, preclinical studies demonstrating that the drug can be rapidly reversed by injecting L-cysteine led to the development of CW002, an intermediate duration molecule that can also be reversed at any time by L-cysteine injection. Clinical trials with CW002 are now underway. The ability to reverse complete paralysis with cysteine dovetails with the established selective aminosteroid binding agent sugammadex, and the recently described universal relaxant binding agent calabadion. Taken together, the concept of rapid reversal at any time raises the question of whether an ultrashort nondepolarizing drug is needed if safe and cost-effective relaxant binding agents are available.

SUMMARY

The gantacurium derivative CW002 is an intermediate duration, nondepolarizing, cysteine-inactivated, neuromuscular blocking drug currently in clinical trials. Like sugammadex reversal of rocuronium, CW002 can be reversed at any time by cysteine injection.

Novel drug development for neuromuscular blockade

Pharmacological advances in anesthesia in recent decades have resulted in safer practice and better outcomes. These advances include improvement in anesthesia drugs with regard to efficacy and safety profiles. Although neuromuscular blockers were first introduced over a half century ago, few new neuromuscular blockers and reversal agents have come to market and even fewer have remained as common clinically employed medications. In recent years, newer agents have been studied and are presented in this review. With regard to nondepolarizer neuromuscular blocker agents, the enantiomers Gantacurium and CW002, which are olefinic isoquinolinium diester fumarates, have shown potential for clinical application. Advantages include ultra rapid reversal of neuromuscular blockade via cysteine adduction and minimal systemic hemodynamic effects with administration.

Independent predictors of delay in emergence from general anesthesia

Some patients with intellectual disabilities spend longer than others in emergence from ambulatory general anesthesia for dental treatment. Although antiepileptic drugs and anesthetics might be involved, an independent predictor for delay of the emergence remains unclear. Thus, a purpose of this study is to identify independent factors affecting the delay of emergence from general anesthesia. This was a retrospective cohort study in dental patients with intellectual disabilities. Patients in need of sedative premedication were removed from participants. The outcome was time until emergence from general anesthesia. Stepwise multivariate regression analysis was used to extract independent factors affecting the outcome. Antiepileptic drugs and anesthetic parameters were included as predictor variables. The study included 102 cases. Clobazam, clonazepam, and phenobarbital were shown to be independent determinants of emergence time. Parameters relating to anesthetics, patients' backgrounds, and dental treatment were not independent factors. Delay in emergence time in ambulatory general anesthesia is likely to be related to the antiepileptic drugs of benzodiazepine or barbiturates in patients with intellectual disability.

New medications and techniques in ambulatory anesthesia

Novel anesthetic and analgesic agents are currently under development or investigation to improve anesthetic delivery and patient care. The pharmacokinetic and analgesic profiles of these agents are especially tailored to meet the challenges of rapid recovery and opioid minimization associated with ambulatory anesthesia practice.

Cucurbit[n]uril type hosts for the reversal of steroidal neuromuscular blocking agents

The ideal neuromuscular blocking agent (NMBA) is regarded as being a non-depolarizing equivalent of succinylcholine, having a rapid onset and short duration of action, with minimal side effects. In the absence of a single drug, the administration of an aminosteroid NMBA, such as rocuronium, followed by reversal using an acetylcholinesterase inhibitor, such as neostigmine, is commonly employed. A different and safer approach to rapidly reversing the action of the NMBA, by encapsulating it with a macrocyclic or acyclic host molecule, such as the cyclodextrin sugammadex or more recently, cucurbituril-type hosts such as cyclic cucurbit[7]uril and the acyclic glycoluril tetramer calabadion 1, is described.

Recovery of residual curarization after red blood cell transfusion

Background

The muscle-relaxing effects of succinylcholine are terminated via hydrolysis by plasma cholinesterase. There are multiple genetic variants of this enzyme and clinical circumstances that might influence the activity of plasma cholinesterase and eventually lead to prolonged neuromuscular blockade following succinylcholine application.

Case Report

Here, we report a parturient woman with atonic bleeding who suffered significant blood loss (hemoglobin 6.0 g·dL⁻¹). For surgical curettage, general anesthesia was performed by using short-acting succinylcholine. By the end of the 105-minute procedure, the patient’s trachea was extubated. After extubation she showed signs of the prolonged neuromuscular blocking action of succinylcholine. At this time, the patient received an AB0-compatible red blood cell transfusion and recovered instantly from neuromuscular blockade. The plasma cholinesterase (3.200 U·L⁻¹) was below the normal range (4.900–12.000 U·L⁻¹). Patient’s blood DNA analysis revealed heterozygously the genetic K variant of plasma cholinesterase. After red blood cell transfusion, serum potassium was elevated (5.7 mmol·L⁻¹; 4.4 mmol·L⁻¹ prior to transfusion).

Conclusions

Pregnancy, blood loss and genetic variation contributed to impairment of plasma cholinesterase. Due to high-speed red blood cell transfusion, hemolytic release of erythrocyte cholinesterase might have terminated the neuromuscular blocking succinylcholine effect.