Neuromuscular interaction between cisatracurium and mivacurium, atracurium, vecuronium or rocuronium administered in combination

Insights into the spectrofluorometric determination of the neuromuscular blocker mivacurium chloride

Fluorescence spectroscopy is gaining interest in the analysis and quantitative determination of different drugs. This study was carried out to investigate the fluorometric properties of the short-acting muscle relaxant mivacurium in its pure form, injection, and human plasma. It is nondepolarizing skeletal muscle relaxant for intravenous (IV) administration. Mivacurium shows a strong native fluorescence in methanol at 317 nm after excitation at 230 nm (Method I). The critical parameters that may influence the fluorescence of this drug were carefully studied. A linear response between concentration and fluorescence was constructed over the concentration range: 20.0 to 400.0 ng/mL with determination coefficient (r²) equal to 0.9998. Additionally, the correlation coefficient of the linear relationship (r) was found to be 0.9999 with a slope = 2.196 and intercept = -16.61. Limits of quantitation and detection were calculated mathematically to be 17.45 and 5.75 ng/mL respectively. Further estimation of mivacurium in spiked human plasma was performed by construction of specific calibration curve and the obtained correlation coefficient was 0.9948. Moreover, the ability to determine mivacurium in the presence of commonly co-administered drugs were investigated including propofol and thiopental. Method II includes the determination of MVC in the presence of propofol utilizing the first derivative synchronous fluorescence spectroscopy. The results of method II indicated acceptable percentage recoveries from 98.88 to 100.75 %. Statistical evaluation of the results revealed satisfactory accuracy and precision.

The median effective dose (ED50) of cis-Atracurium for laryngeal mask airway insertion during general Anaesthesia for patients undergoing urinary surgery

Background

In clinical practice, the laryngeal mask airway is an easy-to-use supraglottic airway device. However, the cis-atracurium dosage for laryngeal mask insertion has not been standardised. We aimed to determine the optimal dose of cis-atracurium using a sequential method for successful laryngeal mask insertion.

Methods

The cohort study protocol is registered at clinicaltrial.gov (NCT-03668262). Twenty-three patients undergoing elective urinary surgery were sequentially administered cis-atracurium doses as follows: 150, 100, 70, 50, 30, and 20 μg·kg^− 1. The main outcome involved the determination of the response to laryngeal mask airway insertion: ≥16 points and < 16 points indicated “satisfactory” and “unsatisfactory” responses, respectively. The median effective dose was estimated using the mean of the seven crossovers from “satisfactory” and “unsatisfactory” responses. The primary outcome involved the determination of the median effective dose (ED50) of cis-atracurium for laryngeal mask airway insertion.

Results

The median effective dose of cis-atracurium was 26.5 μg·kg^− 1 (95% CI 23.6–29.8) using the sequential method. Heart rate was decreased in the 50 μg·kg^− 1 group compared to that in the 30 μg·kg^− 1 group at timepoints T7, T8, and T10 (P = 0.0482, P = 0.0460, and P = 0.0236, respectively), but no difference was observed in the 20 μg·kg^− 1 group. Systolic blood pressure was decreased in the 50 μg·kg^− 1 group compared to that in the 20 μg·kg^− 1 group at timepoints T2, T3, and T4 (P = 0.0159, P = 0.0233, and P = 0.0428, respectively). The train-of-four value was significantly lower in the 50 μg·kg^− 1 group than in the 30 μg·kg^− 1 group at timepoint T3 (P = 0.0326).

Conclusions

The ED50 of cis-atracurium was 26.5 μg·kg^− 1 for laryngeal mask airway insertion.

Trial registration

Clinicaltrial.gov Registry, NCT03668262, Registered on 11 September 2018.

Optimal dose of combined rocuronium and cisatracurium during minor surgery: A randomized trial

BACKGROUND

Combined rocuronium and cisatracurium have synergistic effects. We investigated whether reduced doses are effective during coadministration, by monitoring neuromuscular relaxation during surgery.

METHODS

This randomized, controlled clinical trial was registered at http://clinicaltrials.gov (registration number NCT02495038). The participants were 81 patients scheduled for elective mastoidectomy and tympanoplasty. Participants were assigned to groups, including the intubating dose group (Group I, n = 27; combined ED95 rocuronium and ED95 cisatracurium), the small reduction group (Group S, n = 27; dose reduced by 10% of each ED95), or the large reduction group (Group L, n = 27; dose reduced by 20% of each ED95). Drugs were administered to patients and a timer was started using TOF-Watch monitoring. TOF (train-of-four) was monitored at the ulnar nerve, at a setting of 2 Hz/12 s. We recorded the time to TOF ratio = 0 (onset), time to first TOF ratio > 25% (duration 25%), and TOF 25-75% (recovery index) under total intravenous anesthesia. One-way analysis of variance was used for statistical analyses (α = 0.05, β = 0.2).

RESULTS

There were no significant demographic differences between groups. Group L had a longer duration to onset (mean ± standard deviation, 399.3 ± 147.8 seconds) and shorter duration 25% (39.4 ± 6.8 minutes) compared to Group I (212.8 ± 56.0 s and 51.3 ± 8.47 minutes, respectively) and Group S (230.7 ± 60.6 s and 47.9 ± 10.7 minutes, respectively). There were no other significant differences between groups.

CONCLUSION

Our findings contribute to determining clinically effective combinations of rocuronium and cisatracurium, as well as to predicting the pharmacokinetic characteristics of the synergistic effects. We suggest that reducing doses of both drugs by approximately 10% of their respective ED95 values is sufficient to maintain neuromuscular relaxation during minor surgery.

Synergism between rocuronium and cisatracurium: comparison of the Minto and Greco interaction models

Background

This study was conducted to investigate the pharmacodynamic interaction between rocuronium and cisatracurium using the response surface model, which is not subject to the limitations of traditional isobolographic analysis.

Methods

One hundred and twenty patients were randomly allocated to receive one of the fifteen predefined combinations of rocuronium and cisatracurium. To study single drugs, cisatracurium 0.2, 0.15, or 0.1 mg/kg or rocuronium 0.8, 0.6 or 0.4 mg/kg doses were administered alone. To study the pharmacodynamic interaction, drugs were applied in three types of combination ratio, i.e., half dose of each drug alone, 75% of each single dose of rocuronium and 25% of each single dose of cisatracurium, and vice versa. Train-of-four (TOF) ratio and T1% (first twitch of the TOF presented as percentage compared to the initial T1) were used as pharmacodynamic endpoints, and the Greco and Minto models were used as surface interaction models.

Results

The interaction term α of the Greco model for TOF ratio and T1% measurements showed synergism with values of 0.977 and 1.12, respectively. Application of the Minto model resulted in U₅₀ (θ) values (normalized unit of concentration that produces 50% of the maximal effect in the 0 < θ < 1 region) less than 1 for both TOF ratio and T1% measurements, indicating that rocuronium and cisatracurium exhibit synergism.

Conclusions

Response surface modeling of the interaction between rocuronium and cisatracurium, based on considerations of their effects on muscle relaxation as measured by TOF ratio and T1%, indicated that the two drugs show considerable synergism.

Incidence of postoperative residual neuromuscular blockade after general anesthesia: a prospective, multicenter, anesthetist-blind, observational study

OBJECTIVE

Evidences demonstrate that postoperative residual neuromuscular blockade (rNMB) is a primary and frequent anesthetic risk factor for postoperative complications. This study was designed to mitigate the paucity of data regarding the occurrence and degree of rNMB in a real-life setting.

METHODS

This prospective, multicenter, anesthetist-blind, observational study enrolled 1571 Chinese adults undergoing elective open or laparoscopic abdominal surgery lasting ≤4 hours from 32 hospitals across China. The patients received anesthesia in accordance with routine practice at the study site. Neuromuscular blockade (NMB) was monitored using acceleromyography, with rNMB defined as a train-of-four (TOF) ratio <0.9.

RESULTS

The patients' mean age was 46 years and 71% were female. The procedures included laparoscopic (67%), open abdominal (31%), and laparoscopic to open abdominal (2%). NMB was reversed with neostigmine in 78% of patients. The overall incidence of rNMB at extubation was 57.8%, and the proportions of participant with TOF ratios <0.6, 0.6-0.7, 0.7-0.8, 0.8-0.9 were 22.9%, 6.9%, 11.1% and 16.9%, respectively, immediately prior to endotracheal extubation. Age <45 years (OR = 0.630, 95% CI = 0.496-0.801, p = 0.002), use of one neuromuscular blocking agent (NMBA) (OR = 0.387, 95% CI = 0.243-0.618, p < 0.0001), time from neostigmine administration to endotracheal extubation ≥10 min (OR = 0.513, 95% CI = 0.400-0.658, p < 0.0001) and time from last NMBA administration to endotracheal extubation ≥60 min (OR = 0.902, 95% CI = 0.801-0.989, p = 0411) were correlated with non-rNMB at the time of extubation.

CONCLUSIONS

This observational study demonstrated that the overall incidence of rNMB at the time of endotracheal extubation was high in Chinese patients undergoing abdominal procedures, which necessitates appropriate management in current real-life practice.

CLINICAL TRIAL REGISTRY NUMBER

NCT01871064.

Pharmacodynamic interaction models in pediatric anesthesia

Pharmacokinetic (PK) and pharmacodynamic (PD) models are important tools for summarizing drug dose, concentration, and effect relationships. Co-administration of drugs may alter PK and PD relationships. Traditional methods of evaluating PD interactions include using isoboles, shifts in dose-response curves, or interaction indices based on parameters of potency derived from separate monotherapy and combination therapy analyses. These methods provide an estimation of the magnitude of effect for dose or concentration combinations, but they do not inform us on the time course of that effect, or its associated variability. A better way to investigate PD interactions is to use modeling, and to take advantage of the benefits of population analyses. A population analysis is a statistical method in which a model describing the typical (or population) response, and the variability between individuals within that population, is developed. Models for monotherapy, derived using a population approach, can be combined and extended to incorporate PD interactions between two or more drugs. The purpose of this article was to provide a general road map for understanding and interpreting PD interaction models, including the 'response surface' models. Several types of response surface models exist, and here we review these with examples taken from the literature. We also consider current and future applications for this type of analysis for clinical anesthesia and pediatrics.

A comparison of the clinical duration and recovery characteristics of cisatracurium after priming using rocuronium or cisatracurium: preliminary study

Background

The priming technique can speed up the onset of cisatracurium during intubation. However, there have been no reports on the effect of the priming technique on duration or recovery profile of cisatracurium. Therefore, we attempted to determine whether or not a priming technique with rocuronium or cisatracurium can affect clinical duration or recovery profiles of cisatracurium.

Methods

A total of 36 patients, ASA I and II, who were scheduled to undergo elective surgery, were enrolled. The patients were randomized into three groups and administered different drugs for the priming technique. Patients in group 1 received normal saline (control group). Patients in group 2 received rocuronium (0.06 mg/kg), and those in group 3 received cisatracurium (0.01 mg/kg) as a priming agent. Three minutes after injection of drugs, intubation doses of cisatracurium were administered (Group 1, 0.15 mg/kg; Groups 2 and 3, 0.14 mg/kg). Anesthesia was induced and maintained with propofol and remifentanil. Onset time, clinical duration, recovery index, recovery time, and total recovery time were measured by train of four monitoring.

Results

Onset time in the group 2 was significantly shorter than that of group 1 or 3 (P < 0.05). However, no significant differences in clinical duration, recovery index, recovery time, and total recovery time were observed among the three groups.

Conclusions

Priming with rocuronium for 3 minutes resulted in significantly accelerated onset of cisatracurium. However, it did not affect the clinical duration and recovery profiles of cisatracurium.

Analysis of the rocuronium-vecuronium interaction on tetanic fade based on a generalized response surface model with varying relative potencies

BACKGROUND

Some studies have shown that rocuronium and vecuronium have additive, or synergistic effects on muscle relaxation based on the Loewe additivity. Therefore, we performed a fit of tetanic fade data to a generalized response surface model with varying relative potencies proposed by Kong and Lee (KLGRS) to evaluate the usefulness of KLGRS for capturing the interspersed drug interactions and to characterize the interaction between the two drugs.

METHODS

Left phrenic nerve-hemidiaphragms (Male Sprague-Dawley rats, 150-250 g) were mounted in Krebs solution. Supramaximal electrical stimulation (0.2 ms, rectangular) of 50 Hz for 1.9 s to the phrenic nerve evoked tetanic contractions that were measured with a force transducer. Each preparation was exposed to one of 4 vecuronium concentrations (0.0, 1.5, 2.5, and 3.0 microM), or one of 4 rocuronium concentrations (0.0, 3.0, 4.5, and 5.5 microM). Subsequently the adequate amount of rocuronium was added to a vecuronium bath and that of vecuronium was added to a rocuronium until an 80-90% increase in tetanic fade was achieved. We then fitted the modified KLGRS models to the above data, after which we selected the best model, based on 5 methods for determining goodness of fit. Using this method, we obtained the response surface, as well as contour plots for the response surface (i.e. isoboles), the polynomial function and the interaction index.

RESULTS

The model with the constant relative potency ratio and 8 parameters was found to best describe the results, and this model reflected well the characteristics of the raw data. In addition, the two drugs showed a synergistic interaction in almost every area and an antagonistic one in a very narrow area.

CONCLUSIONS

KLGRS was found to be a useful method of analyzing data describing interspersed drug interactions. The interaction between rocuronium and vecuronium was found to be synergistic.

Acceleromyography and mechanomyography for establishing potency of neuromuscular blocking agents: a randomized-controlled trial

BACKGROUND

Acceleromyography (AMG) is increasingly being used in neuromuscular research, including in studies establishing the potency of neuromuscular blocking and reversal agents. However, AMG is insufficiently validated for use interchangeably with the gold standard, mechanomyography (MMG) for this purpose. The aim of this study was to compare AMG and MMG for establishing dose-response relationship and potency, using rocuronium as an example.

METHODS

We included 40 adult patients in this randomized-controlled single-dose response study. Anaesthesia was induced and maintained with propofol and opioid. Neuromuscular blockade was induced with rocuronium 100, 150, 200 or 250 microg/kg. Neuromuscular monitoring was performed with AMG (TOF-Watch SX) with pre-load (Hand Adapter) at one arm and MMG (modified TOF-Watch SX) on the other, using 0.1 Hz single twitch stimulation. Dose-response relationships were determined for both recording methods using log (dose) against probit (maximum block). The obtained slopes of the regression lines, ED(50), ED(95) and the maximum block were compared.

RESULTS

The ED(50) and ED(95) [95% confidence interval (CI)] for AMG were 185 microg/kg(167-205 microg/kg) and 368 microg/kg(288-470 microg/kg), compared with 174 microg/kg(159-191 microg/kg) and 338 microg/kg(273-418 microg/kg) for MMG. There were no statistically significant biases in maximum block, ED(50), ED(95) or slopes obtained with the two methods.

CONCLUSION

Our results indicate that any possible difference between AMG and MMG is so small that it justifies AMG to be used for establishing the potency of neuromuscular blocking agents. However, the wide CIs show that we cannot rule out a 13% higher ED(50) and a 26% higher ED(95) for AMG.

Synergy between pairs of competitive antagonists at adult human muscle acetylcholine receptors

BACKGROUND

Synergistic neuromuscular blocking effects have been observed clinically with certain pairs of nicotinic acetylcholine receptor (nAChR) competitive antagonists. The mechanism for synergy has not been elucidated. We tested the hypothesis that synergy arises from a differential selectivity of antagonists for the two ligand binding sites on adult human nAChR.

METHODS

We expressed nAChR in BOSC23 cells. We applied ACh with or without antagonists to outside-out patches and measured macroscopic currents at room temperature. We determined the IC(90) for (+)-tubocurarine, metocurine, pancuronium, vecuronium, cisatracurium, rocuronium, and atracurium. For 15 combinations of two antagonists, we determined the IC(90) for one antagonist in the presence of the IC(70) of a second antagonist. We constructed isobolograms for 90% inhibition. For single antagonists, we measured inhibition of receptors containing mutations in the epsilon- and delta-subunits to determine site selectivity.

RESULTS

Two pairs of antagonists, metocurine+cisatracurium and cisatracurium+ atracurium exhibited additive inhibition. Ten combinations, including (+)-tubocurarine+ pancuronium and pancuronium+vecuronium, were highly synergistic such that the combination was two to three times more effective than expected for additivity. Three combinations were 1.5-1.6 times more effective than expected for additivity. Inhibition by (+)-tubocurarine and metocurine was sensitive to mutations in the epsilon-subunit only. Vecuronium was affected by the delta-subunit mutation only. Inhibition by other antagonists was decreased by mutations in either subunit.

CONCLUSIONS

Many combinations of antagonists exhibited synergistic effects on adult human nAChR. Synergy was observed with structurally similar and dissimilar antagonists. The degree of synergy did not always correlate well with site specificity assayed with mutants. In some, but not all cases, the synergy at the receptor level correlated with clinical determinations of synergy. We conclude that the synergistic actions of muscle relaxants can be partially explained by direct interactions with adult human nAChR.

Influence of acute normovolaemic haemodilution on the dose-response relationship and time course of action of cisatracurium besylate

BACKGROUND

Acute normovolaemic haemodilution (ANH) is an efficacious blood conservation strategy aiming at avoiding allogeneic blood transfusion. ANH was shown to increase the potency of vecuronium, atracurium, and rocuronium. The aim of our study was to investigate whether cisatracurium potency is altered with ANH.

METHODS

Using the Relaxometer mechanomyograph, we compared cisatracurium dose-response relationship and time course of action in 60 patients randomly allocated to the ANH or control groups. Patients in each group were randomly allocated to receive one of three cisatracurium doses (30, 40, 50 microg kg(-1)) followed by a second supplemental dose to reach a total of 100 microg kg(-1).

RESULTS

ANH did not result in a significant shift in cisatracurium log dose-probit dose-response curve. There was no significant difference in mean (95% confidence intervals) ED(50), ED(90), and ED(95) (effective doses required for 50, 90, and 95% first twitch depression) between the ANH group [29.5 (27-32), 50.4 (47.4-53.4), 58.7 (55.3-62) microg kg(-1)] and the control group [28.2 (25.3-31), 47.6 (44.9-50.3), 55.3 (52.5-58.1) microg kg(-1)], whereas there was no difference in mean (SD) Dur(25) and Dur(0.8) (time until 25% first twitch and 0.8 train-of-four ratio recoveries) between the ANH group [40.8 (5.9), 64.7 (8.4) min] and the control group [42.2 (7.6), 66.5 (10.7) min].

CONCLUSIONS

Our results demonstrated that unlike other previously reported neuromuscular blocking drugs, ANH did not alter cisatracurium potency. Thus, cisatracurium would be the neuromuscular blocking drug of choice in patients who undergo surgery with ANH, as no dose adjustments are required.

Pharmacodynamic interactions between cisatracurium and rocuronium

The onset and duration of maintenance doses of neuromuscular blocking drugs may be influenced by the original neuromuscular blocking drug used. We assessed the effect of the interaction between steroidal and benzo-isoquinolinium compounds on the clinical duration of maintenance doses of cisatracurium. Sixty adult patients undergoing anesthesia with isoflurane, nitrous oxide, and oxygen were randomized to receive the following: Group I = rocuronium 0.6 mg/kg followed by cisatracurium 0.03 mg/kg when the first twitch in the train-of-four (TOF) recovered to 25%, Group II = cisatracurium 0.15 mg/kg followed by cisatracurium 0.03 mg/kg, and Group III = rocuronium 0.6 mg/kg followed by rocuronium 0.15 mg/kg. Neuromuscular blockade was monitored using acceleromyography (TOF-Guard, Boxtel, The Netherlands). The clinical duration (mean +/- SD) of the first 2 maintenance doses was 41 +/- 10, 31 +/- 7++, and 25 +/- 8++ min, and 39 +/- 11, 30 +/- 6+, 29 +/- 9* min in Groups I-III, respectively (*P < 0.05, +P < 0.01, ++P < 0.001; Group I versus II and III). Thus, the clinical duration of the first two maintenance doses of cisatracurium was prolonged when administered after rocuronium.

IMPLICATIONS

We assessed the clinical effect of administering cisatracurium after an intubating dose of rocuronium in 60 patients undergoing isoflurane/nitrous oxide and oxygen anesthesia. The clinical duration of the first two maintenance doses of cisatracurium administered after rocuronium was significantly prolonged. This supports the contention that combinations of structurally dissimilar neuromuscular blocking drugs result in a synergistic effect.

[Drug interactions and the anesthesiologist]

Eines der Grundprinzipien der modernen Anästhesie ist die Kombination unterschiedlicher Pharmaka aus verschiedenen Substanzgruppen. Zusätzlich sehen sich Anästhesisten häufig mit der umfangreichen medikamentösen Dauertherapie chronisch kranker Patienten konfrontiert. Werden zwei oder mehrere Medikamente gleichzeitig appliziert, kann sich der pharmakologische Effekt von der Summe der einzeln verabreichten Substanzen unterscheiden. Das kann erwünscht, aber für den Patienten auch potenziell gefährlich sein. Die Wahrscheinlichkeit einer unerwünschten Arzneimittelwechselwirkung steigt exponentiell mit der Anzahl der verabreichten Medikamente und kann sowohl auf pharmazeutischer, pharmakodynamischer wie pharmakokinetischer Ebene entstehen. Obwohl die Fülle der Interaktionsmöglichkeiten enorm und die Komplexität der Arzneimittelwechselwirkungen schwer greifbar und zu identifizieren sind, gelten ernsthafte Medikamenteninteraktionen in der Anästhesie allgemein als vorhersehbar. Neben der Erkennung der Risikofaktoren wie Leber- und Niereninsuffizienz, ASA-Status sowie metabolische und endokrine Veränderungen des Patienten sind grundlegende Kenntnisse und ein Verständnis der allgemeinen und speziellen Pharmakologie notwendig, um unerwünschte Arzneimittelwechselwirkungen zu verhindern.

Isobolographic analysis of non-depolarising muscle relaxant interactions at their receptor site

Administration of certain combinations of non-depolarising muscle relaxants produces greater than expected neuromuscular blockade. Synergistic effects may be explained by drug interactions with the postsynaptic muscle nicotinic acetylcholine receptor. To investigate this hypothesis, the adult mouse muscle nicotinic acetylcholine receptor (alpha(2)beta delta epsilon) was heterologously expressed in Xenopus laevis oocytes and activated by the application of acetylcholine (10 microM). The effects of five individually applied muscle relaxants and six combinations of structurally similar and dissimilar compounds were studied. Drug combinations containing equipotent concentrations of two agents were tested and dose-response curves were determined. All compounds tested alone and in combination produced rapid and readily reversible, concentration-dependent inhibition. Isobolographic and fractional analyses indicated additive interactions for all six tested combinations. These findings suggest that synergistic neuromuscular blocking effects, observed for the administration of certain combinations of muscle relaxants, do not result from purely postsynaptic binding events at the muscle nicotinic acetylcholine receptor, but rather from differential actions on pre- and postsynaptic sites.

Intubating conditions and blockade after mivacurium, rocuronium and their combination in young and elderly adults

PURPOSE

Mivacurium-rocuronium combinations have been demonstrated to be more potent than either drug given alone. Combinations were compared with mivacurium and rocuronium, with respect to onset, intubating conditions, and duration of action in young and elderly adults.

METHODS

Fentanyl-propofol-N2O-isoflurane anesthesia was given to ASA I and II adults aged 18-65 yr (45 patients) and over 66 yr (45 patients). In this blinded randomized study, we compared accelerographic adductor pollicis response and visual assessment of response to facial nerve stimulation after 0.25 mg x kg(-1) mivacurium, 0.6 mg x kg(-1) rocuronium, and a combination of 0.08 mg kg(-1) mivacurium plus 0.2 mg x kg(-1) rocuronium. Intubating conditions at 2.5 min were rated as excellent, good, fair or poor.

RESULTS

Onset times were similar for all drugs regimens and for both age groups (204-276 sec at the thumb; 142-196 sec at the eye) (P<0.05 between muscles). Intubating conditions were similar in all groups, and rated good or excellent, except in two subjects. In young patients duration to 25% recovery was longer (P<0.05) for rocuronium (mean +/- SD) (39+/-11 min) than for either mivacurium (23+/-6 min), or the combination (27+/-7 min). Duration was prolonged in the elderly for rocuronium (54+/-17 min), and the combination (35+/-11 min), but not for mivacurium (24+/-6 min).

CONCLUSIONS

Mivacurium-rocuronium combinations yield onset times and intubating conditions similar to either parent agent with only two thirds as much total drug. Duration for such a mixture is similar to that of mivacurium in young adults and slightly prolonged in the elderly.