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PubMed1986

Pharmacokinetics and pharmacodynamics of vecuronium and pancuronium in anesthetized children.

The pharmacokinetics and pharmacodynamics of vecuronium and pancuronium were determined in 12 children (3-6 yr) undergoing minor surgery under 60% nitrous oxide, 1 MAC halothane anesthesia. When the level of anesthesia and the electromyograph (EMG) recording of the adductor pollicis were stable, an intravenous bolus of vecuronium (100 micrograms/kg) or pancuronium (100 micrograms/kg) was administered. Plasma concentrations of the two muscle relaxants were determined for 6 hr after the administration by means of a fluorimetric assay followed by a thin layer chromatography. Plasma concentrations of vecuronium and pancuronium declined biexponentially in children and no metabolites could be detected in plasma. The elimination half-lives of vecuronium and pancuronium did not differ significantly. The volume of distribution at steady state (Vdss) was greater (P less than 0.05) after vecuronium (320 +/- 181 ml/kg; mean +/- SD) than after pancuronium (203 +/- 36 ml/kg). Plasma clearance of vecuronium (2.8 +/- 0.9 ml X min-1 X kg-1) was greater than that of pancuronium (1.7 +/- 0.2 ml X min-1 X kg-1; P less than 0.05). Plasma concentrations measured at 10%, 50%, or 90% recovery of the EMG response did not differ significantly for vecuronium and pancuronium. Thus the shorter duration of action of vecuronium is probably due to its greater apparent volume of distribution, as well as to its higher plasma clearance. Thus although the elimination half-lives are comparable, the plasma disappearance of vecuronium is more rapid than that of pancuronium.

Anesthesia, General↗
PubMed1987

Antagonism of pancuronium and tubocurarine blocks by edrophonium or neostigmine: a comparative study.

Edrophonium 0.5 and neostigmine 0.05 mg kg-1 were compared as antagonists of pancuronium and tubocurarine-induced neuromuscular blocks, at varying degrees of recovery, in groups of 20 patients each. Adequate antagonism was defined as attaining a sustained train-of-four (TOF) ratio of 0.7 or more. Administration of edrophonium was associated with a more rapid onset of action (17 s with both relaxants with edrophonium, and 31 s and 29 s with neostigmine with pancuronium and tubocurarine, respectively), and a shorter time to attain a TOF ratio of 0.7 (74 s and 48 s with edrophonium and 230 s and 293 s with neostigmine for pancuronium and tubocurarine blocks, respectively). However, whereas neostigmine administration provided adequate antagonism in all 20 patients given pancuronium and in 19 out of 20 patients given tubocurarine, edrophonium failed to achieve adequate antagonism in six patients after pancuronium and eight patients after tubocurarine. The majority of these patients had shown three or less responses to a TOF stimulation prior to antagonism. Two separate groups of 10 patients each with relatively deeper pancuronium or tubocurarine blocks (three or less responses to TOF stimulation) were given edrophonium in a dose of 1.0 mg kg-1. However, adequate antagonism even with this dose of edrophonium was attained in only two out of 10 patients given pancuronium and in five out of 10 patients given tubocurarine. It is concluded that edrophonium is unreliable for antagonism of relatively deep blocks by pancuronium or tubocurarine and that neostigmine is the preferred and more reliable antagonist.

Adult↗
PubMed1983

Heterogeneity of binding sites on cardiac muscarinic receptors induced by the neuromuscular blocking agents gallamine and pancuronium.

The binding of [3H]quinuclidinyl benzilate ([3H]QNB) to cardiac muscarinic receptors was inhibited not only by classical muscarinic antagonists but also by nicotinic blocking agents and inhibitors of acetylcholinesterase. Gallamine, pancuronium, ambenonium, and decamethonium were the most potent of these agents examined. All of the nicotinic antagonists with significant muscarinic receptor activity had two or three quaternary nitrogens, and the potency of a series of these compounds was a function of the distance between quaternary nitrogens. The effects of gallamine and pancuronium were studied in detail because these neuromuscular blocking agents showed heterogeneity in their binding to cardiac muscarinic receptors, whereas classical muscarinic antagonists such as QNB and atropine did not. Gallamine did not compete for all of the [3H]QNB binding sites on atrial membranes, but left at least 20% of [3H]QNB binding unaffected. Curves of pancuronium competition for [3H]QNB binding were shallow, consistent with two binding sites for pancuronium, with approximately 20% having low affinity. Additionally, in the presence of gallamine or pancuronium, [3H]QNB binding sites were no longer homogeneous, and Scatchard plots became nonlinear. Guanine nucleotides did not alter the effect of gallamine or pancuronium on [3H]QNB binding. Gallamine and pancuronium showed no agonist activity but, like atropine, completely antagonized muscarinic receptor-mediated inhibition of cyclic AMP formation. However, differences in the behavior of gallamine and atropine suggested that gallamine was not a purely competitive antagonist. Gallamine did not protect against receptor alkylation by propylbenzilylcholine mustard, and [3H]QNB dissociation was apparently slowed by gallamine. We interpret our data to suggest that gallamine not only competes for [3H]QNB binding sites, but also binds at a secondary site on the receptor, forming a ternary complex with [3H]QNB. Heterogeneity in ligand binding is proposed to result from the dual actions of gallamine and pancuronium as ligands at both primary and secondary sites on the cardiac muscarinic receptor.

Animals↗
PubMed1983

Plasma binding of pancuronium: effects of age, sex, and disease.

The extent of pancuronium binding in plasma in controversial due to a lack of definitive studies in human plasma. The degree of pancuronium binding in human plasma and the concomitant effects of age, sex, and renal disease on drug binding were determined by equilibrium dialysis using [3H]pancuronium. The free fraction of pancuronium was 93.2 +/- 1.6% in male subjects and 88.9 +/- 2.5% in adult nonpregnant female subjects, indicating that pancuronium is not highly protein bound. The free fraction in newborns and their mothers was 91.0 +/- 1.8% and 89 +/- 1.3%, respectively. There were no significant differences between the plasma binding of pancuronium in men, nonpregnant women (whether on oral contraceptives or not), pregnant women, or neonates. The free fraction of pancuronium was unaltered (90.7 +/- 2.1%) in patients with severe renal disease. We therefore conclude that the binding of pancuronium in human plasma is very low and that age, sex, oral contraceptives, pregnancy, and renal disease do not influence the plasma binding of this drug.

Adult↗
PubMed1980

Predetermination of dose requirement of pancuronium.

The neuromuscular sensitivity of 71 patients (A.S.A. class I or II) was tested by scoring on a scale from 1 to 6 the ability to lift the upper eyelid 2 minutes after pretreatment with 1 mg of pancuronium. Subsequently, each patient also received an additional "intubation dose" pancuronium (in milligrams) equal to the eye-opening test score (group I), or either 1 mg (group II) or 2 mg (group III) in excess. The resultant depression of the neurally evoked muscle response of the little finger was quantified by another score (the response score) which allowed for assessment of neuromuscular block beyond the limit of 100% depression of the twitch. The criteria for the response score, in the response score, in the order of increasing magnitude of block, were: (1) visible twitch responses to all 4 of the train-of-four stimulation remained; (2) part of the train-of-four twitches was eliminated; (3) all twitches were eliminated; (4) tetanus was eliminated; (5) post-tetanic twitch following a 5-second 50 Hz tetanus was also eliminated; and (6) not even the post-tetanic twitch became elicitable again in 30 minutes. It was found that 1 mg of pancuronium depressed the eye-opening score to 4.0 +/- 0.2, from 5.1 +/- 0.1 (mean +/- SEM, p < 0.01). Following the additional "intubation dose" of pancuronium, patients in group I had an average response score of 2.2 +/- 0.3, those in group II a score of 3.4 +/- 0.2, and those in group III, a score of 4.8 +/- 0.6. Each additional 1 mg of pancuronium (increasing from group I to III) linearly increased the average response score. In terms of frequency response, patients in group I had more than a 50% change of being scored 1, while those in group II had a greater than 50% chance of being scored 3, 4, or 5, and those in group III had more than a 50% chance of being scored 6. It is concluded that sensitivity to pancuronium can be quantified by the ptotic response to a 1-mg test dose of pancuronium, and that a sensitivity-adjusted additional "intubation dose" of pancuronium can be predetermined in individual patients.

Adult↗
PubMed1993

Comparison of atracurium and pancuronium in mechanically ventilated neonates.

OBJECTIVE: To compare haemodynamic and gas exchange effects after either atracurium or pancuronium given to ventilated neonates with respiratory failure. DESIGN: In this prospective study neonates were alternately assigned to receive either atracurium or pancuronium, intravenously. SETTING: Paediatric and neonatal ICU in a teaching hospital. PATIENTS: 21 ventilated neonates with mean birth weight of 2293 g, suffering from respiratory distress syndrome, meconium aspiration syndrome or pneumonia were included in the study. Patients were entered if they were breathing out of phase with the ventilator and required FIO2 > 0.4 and peak inspiratory pressure (PIP) > 15 cm H2O. Exclusion criteria were unstable haemodynamics or a pneumothorax. INTERVENTIONS: Heart rate, respiratory rate, invasive blood pressure and transcutaneous oxygen tension were monitored continuously. IV atracurium (0.3 mg/kg) or pancuronium (0.1 mg/kg) were administered. Arterial blood gas analysis was performed before and 10 min after injection of muscle relaxant. MEASUREMENTS AND RESULTS: Atracurium caused a significant decrease in heart rate (p < 0.05), systolic and mean blood pressure (p < 0.01). There was also a slight decrease in PaO2 and PaCO2 (n.s.). Administration of pancuronium resulted in an increase in heart rate (p < 0.01) and a slight decrease of blood pressure (n.s.). PaCO2 remained unchanged, whereas PaO2 increased slightly (n.s.). The PtcO2 index (PtcO2/PaO2) decreased after atracurium and did not change after pancuronium (both n.s.). With both drugs a slight increase in alveolar to arterial oxygen tension difference was observed (n.s.). There was one episode of hypotension and one of hypoxaemia--both after pancuronium. CONCLUSION: Both drugs may be used for muscle relaxation in neonates with respiratory failure. Atracurium however causes more cardiovascular depression, whereas the effect of pancuronium may be difficult to predict.

Atracurium↗
PubMed2005

Interaction between mivacurium and pancuronium: impact of the order of administration.

INTRODUCTION: Potentiation of mivacurium by low-dose pancuronium is mostly due to an inhibition of plasma butyryl cholinesterase (BchE) resulting in a decreased rate of hydrolysis of mivacurium. Nevertheless, an interaction at the receptor site could not be ruled out. By changing the order of the muscle relaxant injections, we may lessen the pharmacokinetic interaction and assess the impact at the acetylcholine receptor level. METHODS: Twenty patients scheduled for general anesthesia with propofol and fentanyl, and isoflurane were randomized into two groups receiving, mivacurium 100 microg kg-1 followed by pancuronium 15 microg kg-1 (group 1) or pancuronium 15 microg kg-1 followed by mivacurium 100 microg kg-1 (group 2). BchE before and after injection of each relaxant was measured. Neuromuscular block was assessed with a force transducer at the adductor pollicis measuring the elicited twitch to ulnar nerve stimulation. RESULTS: The neuromuscular block was greater when pancuronium was administered before mivacurium (100% versus 96+/-3%; P<0.05). Times to recovery of the elicited twitch response to 25% and 75% of control value were increased by 100% (P<0.05). After pancuronium, decreases in BchE of 11% and 14% in groups 1 and 2 were observed, respectively. CONCLUSION: Interaction between mivacurium and low dose pancuronium is significant only when mivacurium is injected after pancuronium.

Aged↗
PubMed1982

The interaction of pancuronium with cardiac and ileal muscarinic receptors.

The activity of pancuronium as a muscarinic antagonist was compared in atria from several species and in guinea-pig ileal longitudinal muscle. Pancuronium had a 20-fold greater affinity for muscarinic receptors mediating the negative inotropic response to carbachol (CCh) in the guinea-pig left atrium (pKB = 6.96) than for muscarinic receptors in guinea-pig ileal longitudinal muscle (pKB = 5.65). The greater affinity of pancuronium in the atria was not due to an interaction with noradrenergic neurones as pretreatment of atria with propranolol (3 microM) or of guinea-pigs with 6-hydroxydopamine (400 mg/kg total dose) failed to modify the degree of inhibition exhibited in atria. The affinities of pancuronium for muscarinic receptors mediating negative inotropic responses in the kitten left atrium or negative chronotropic responses in guinea-pig or rabbit right atria were not significantly different from that in the guinea-pig left atrium (P greater than 0.05) but the affinity of pancuronium for muscarinic receptors in ileal longitudinal muscle was significantly different (P less than 0.05) from all values obtained in the cardiac preparations suggesting differences in the binding of the antagonist in smooth and cardiac muscle. The A-S plot for pancuronium (0.27 microM-0.20 mM) as an antagonist of negative inotropic responses to CCH was non-linear, showing a flattening at the higher concentrations of pancuronium. This was not apparent in the A-S plot for the inhibition of tonic responses to CCh in ileal longitudinal muscle.

Animals↗
PubMed1993

Pancuronium, vecuronium, and heart rate during anesthesia for aortocoronary bypass operations.

To determine the effects of pancuronium and vecuronium on heart rate, 90 patients scheduled for aortocoronary bypass were randomly assigned to one of three groups (30 patients each) which received vecuronium 100 micrograms[sdot]kg-1, pancuronium 100 micrograms[sdot]kg-1, or a mixture of vecuronium (50 micrograms[sdot]kg-1) and pancuronium (50 micrograms[dot]kg-1) in a double-blind fashion during induction of anesthesia. All patients were premedicated with lorazepam prior to surgery, hence avoiding the effects of scopolamine. Our results showed no significant increase in heart rate from the administration of pancuronium, following administration of this drug the heart rate increased by only four beats per minute. The heart rate was unchanged after the mixture, but decreased by twelve beats per minute after vecuronium (P < 0.05). The heart rate response differed by 16 beats per minute between pancuronium and vecuronium. All patients who received either of the neuromuscular relaxants and who were on beta blockers showed a decrease in heart rate. In this study, the administration of pancuronium after an adequate induction dose of fentanyl did not cause tachycardia. We therefore feel that pancuronium still has a role in cardiac anesthesia, especially as the newer muscle relaxants such as vecuronium, pipecuronium and doxacurium are significantly more expensive.

Aged↗
PubMed1977

Bradycardia during antagonism of pancuronium-induced neuromuscular block.

Heart rate was compared in matched patients during antagonism of neuromuscular block induced by tubocurarine, pancuronium or alcuronium with neostigmine 0.03 mg kg-1 preceded by atropine 0.015 mg kg-1. The frequency of bradycardia was greater during antagonism of pancuronium compared with alcuronium. Although there was a difference between the group receiving pancuronium and that receiving tubocurarine, it was not statistically significant. The decrease in heart rate was more rapid and profound in the pancuronium group; seven of the 15 patients who received pancuronium required an additional dose of atropine as compared with only one patient who received tubocurarine. However, the difference in heart rate between those who received pancuronium and those receiving tubocurarine was short-lasting, whereas the heart rate of those who received alcuronium was higher than that in the other groups during the entire 60-min period of observation. The findings with pancuronium may be a result of its inhibitory effect on serum cholinesterase.

Adult↗
PubMed1978

Pancuronium pharmacokinetics in patients with liver cirrhosis.

The serum and urinary concentrations of pancuronium were measured in 14 surgical patients with cirrhosis and 12 patients free from liver disease undergoing abdominal surgery. A two-compartment open model was used in the pharmacokinetic analysis of the data. A two-fold increase in both the distribution half-life (T 1/2 alpha) from 11 min to 24 min and in the elimination half-life (T 1/2 beta) from 114 min to 208 min was observed in patients with cirrhosis. In these individuals, the total apparent volume of distribution of pancuronium was increased by 50%. Plasma clearance of pancuronium was decreased by 22%. No significant difference was found in the urinary excretion and biotransformation pattern of pancuronium. These results suggest that there is a risk of prolonged duration of action of pancuronium in patients with cirrhosis. In these patients, the initial dose to achieve adequate muscle relaxation is high and simultaneously there is slow disappearance of pancuronium from plasma. These alterations are mainly a consequence of the increase in the distribution volume of pancuronium in patients with cirrhosis.

Abdomen↗
PubMed1984

Dose-response relationships and neuromuscular blocking effects of vecuronium pancuronium during ketamine anaesthesia.

The dose-response curves of vecuronium and pancuronium were compared during ketamine anaesthesia in 60 patients (ASA I). The relationship between the probit transformed depression of twitch height and the logarithm of the dose was analysed by linear regression. Vecuronium was found to be 1.2 times more potent than pancuronium. ED50 of vecuronium and pancuronium were 30.5 microgram kg-1 and 37.0 microgram kg-1, and the ED95 45.6 microgram kg-1 and 59.5 microgram kg-1, respectively. Using equipotent doses of vecuronium and pancuronium (1.6 ED95) indices of neuromuscular blockade were compared in a further 20 patients (ASA I). No statistically significant difference was found in onset time. The duration of action following vecuronium was significantly shorter than after pancuronium. The time to 25% recovery of twitch height following vecuronium 73 microgram kg-1 was 22.2 min compared with 66.6 min following pancuronium 99 microgram kg-1. Following supplementary doses of vecuronium, a statistically significant increase in duration of action was seen following the fourth and fifth doses. Reversal time of vecuronium to a train-of-four ratio of 0.7 was significantly shorter than that of pancuronium (8.3 min and 13.6 min, respectively).

Adult↗
PubMed1997

Interactions between mivacurium and pancuronium.

We have compared the dose-response relationships of mivacurium, pancuronium and their combination, and examined the interactions by isobolographic and fractional analyses. We studied 70 adult patients during nitrous oxide-fentanyl-propofol anaesthesia. The dose-response curves were determined by probit analysis. The ED95 and ED50 values for mivacurium were 84.2 (95% confidence interval 80.2-88.1) micrograms kg-1 and 46.2 (40.2-52.1) micrograms kg-1, respectively. Corresponding values for pancuronium were 68.5 (63.7-73.2) micrograms kg-1 and 40.7 (35.5-45.9) micrograms kg-1, respectively. Isobolographic and fractional analyses of the mivacurium-pancuronium combination demonstrated a synergistic interaction. An additional 30 patients were allocated randomly to receive either mivacurium 84.2 micrograms kg-1 (n = 15) or pancuronium 68.5 micrograms kg-1 (n = 15). When the first twitch (T1) of TOF recovered to 25%, each patient received mivacurium 46.2 micrograms kg-1. The times after administration of mivacurium until T1 25% in the mivacurium-pancuronium group were 6.4 (3.5-9.4) min and 49.8 (44.7-54.9) min, respectively (P < 0.0001). We conclude that the combination of mivacurium and pancuronium was synergistic and after pancuronium-induced neuromuscular block, mivacurium became a longer acting agent than the shorter agent.

Adult↗
PubMed1979

Pre- and postsynaptic effects of pancuronium at the neuromuscular junction of the mouse.

The dose-effectiveness of pancuronium as it relates to membrane potentials, action potentials, electrical membrane constants, miniature endplate potentials, endplate potentials, and quantal release was studied in murine phrenic nerve-diaphragm preparations in vitro. Emphasis was placed on comparison of presynaptic with postsynaptic effects of pancuronium under similar experimental conditions. At low concentrations of pancuronium (5 X 10(-8) g/ml or less), no presynaptic effect was found. At high concentration (5 X 10(-7) g/ml), pancuronium depressed quantal release to 26 per cent of control in cut-fiber preparations and 40 per cent of control in high-magnesium preparations. Postsynaptic effects as measured by the amplitude of miniature endplate potentials and relative depolarization induced by 20 microns carbachol, revealed depression to 16 and 22 per cent of control, respectively, at a pancuronium concentration of 5 X 10(-7) g/ml. Pancuronium had no effect on directly elicited action potentials and electrical membrane constants. The authors conclude that presynaptic as well as postsynaptic effects of pancuronium in paralytic doses are essential in contributing to the total efficacy of neuromuscular depression.

Action Potentials↗
PubMed1985

Adverse effects of pancuronium during high-dose fentanyl anesthesia for coronary artery bypass grafting.

Using a randomized double-blind protocol, the authors prospectively compared three nondepolarizing muscle relaxants with respect to their influence on hemodynamics and on the electrocardiogram. Thirty-three patients undergoing elective coronary artery bypass grafting (CABG) with high-dose (100 micrograms/kg) fentanyl anesthesia were studied. Patients received 1.5 X ED95 of either pancuronium (n = 12), metocurine (n = 9), or a metocurine-pancuronium combination (4:1 ratio by weight) (n = 12) for muscle relaxation. Heart rate and rate pressure product (RPP) were significantly higher postinduction in the pancuronium group. Myocardial ischemia, indicated by new ECG ST-segment depression occurred significantly more frequently, and exclusively, in the pancuronium group. The authors' data suggest that since pancuronium is associated with tachycardia and an increased incidence of myocardial ischemia, it is best avoided in patients with severe coronary artery disease undergoing CABG with high-dose fentanyl. Either metocurine or the metocurine-pancuronium combination provides greater hemodynamic stability, without precipitating myocardial ischemia, and can be safely and effectively substituted for pancuronium.

Anesthesia↗
PubMed1995

Double-blind, randomized, multicenter study of doxacurium vs. pancuronium in intensive care unit patients who require neuromuscular-blocking agents.

OBJECTIVE: To compare the neuromuscular-blocking and hemodynamic effects of doxacurium vs. pancuronium administered by intermittent bolus to intensive care unit (ICU) patients who required neuromuscular block to facilitate mechanical ventilation for > or = 24 hrs. DESIGN: A multicenter, prospective, double-blind, randomized study comparing doxacurium, a new benzylisoquinolone neuromuscular-blocking agent, with pancuronium. SETTING: ICUs of three tertiary care hospitals. PATIENTS: Forty critically ill patients (29 male, 11 female) with an average age of 52.5 yrs (range 19 to 80). INTERVENTIONS: With approval of our Institutional Review Boards and after obtaining informed consent, 40 critically ill patients were entered into the study. Histories and the results of physical examinations were recorded, laboratory data were collected, and Acute Physiology and Chronic Health Evaluation (APACHE) II scores were calculated during the 8 hrs before the start of the study medication. Patients received either doxacurium (initial dose of 0.04 mg/kg) or pancuronium (initial dose of 0.07 mg/kg) by bolus injection with continuous measurement of vital signs every minute for 15 mins. We measured the degree of neuromuscular blockade using a peripheral-nerve stimulator to measure the Train-of-Four count. Patients were rebolused (doxacurium dose of 0.025 mg/kg, pancuronium dose of 0.05 mg/kg) based on clinical criteria, which were substantiated by measurement of the Train-of-Four count. The neuromuscular-blocking drugs were stopped when the patient no longer required paralysis or after 5 days of therapy, whichever came first. Group comparisons were made using repeated measures analysis of variance, Fisher's exact test, and two sample t-tests, when appropriate. Spearman's rank-correction coefficients were calculated to assess the relationship of onset time and recovery time with all baseline laboratory values and the APACHE II scores. A p < .05 was used to establish statistical significance. MEASUREMENTS AND MAIN RESULTS: There were no differences between the two groups with respect to age, gender, or APACHE II scores. There were no differences between groups in terms of adverse experiences, nor with respect to time of onset of block, number of doses, or the duration of neuromuscular blockade (2.6 vs. 2.2 days for doxacurium vs. pancuronium, respectively). There was a statistically significant increase in heart rate after the initial dose of pancuronium (120 +/- 23 vs. 109 +/- 22 beats/min postinjection vs. preinjection, respectively; p < .05) without any differences noted after doxacurium (107 +/- 21 vs. 109 +/- 21 beats/min, respectively). Furthermore, once neuromuscular block was discontinued, the pancuronium group had a more prolonged and variable recovery time (279 +/- 229 mins) compared with the doxacurium group (138 +/- 46 mins, p < .05). CONCLUSIONS: In critically ill patients requiring neuromuscular block for > 24 hrs, doxacurium was well tolerated without evidence of tachycardia and with a relatively prompt recovery profile.

APACHE↗
PubMed1987

The interaction of pancuronium and vecuronium with cardiac muscarinic receptors.

The interaction of vecuronium, a monoquaternary analogue of pancuronium, with the cardiac muscarinic receptors in canine hearts was investigated in vitro by [3H] QNB binding assay and compared with that of pancuronium. Both pancuronium and vecuronium, which are nicotinic antagonists of competitive types, inhibited the binding of [3H] QNB to cardiac muscarinic receptors with values of IC50 of 5.41 X 10(-7) mol/l and 3.97 X 10(-6) mol/l respectively. According to the Kd and Bmax values on the Scatchard plot, pancuronium, while not influencing the number of receptors, had a 3-fold greater inhibitory effect than vecuronium on the affinity of the muscarinic receptors. The KI values of vecuronium and pancuronium showed that pancuronium had a 7.3-fold greater affinity with the receptors than vecuronium. We concluded that vecuronium had a direct inhibitory action on the binding of [3H] QNB to the canine heart muscarinic receptors, but this action was much weaker than pancuronium.

Animals↗
PubMed1989

Atracurium and pancuronium in renal insufficiency.

The duration and possible accumulation of atracurium and pancuronium were studied in 59 patients (29 anephric and 30 normal) anaesthetized with 0.5% halothane in O2/N2O and supplemented by fentanyl. Equipotent doses of atracurium (0.5 mg.kg-1) and pancuronium (0.1 mg.kg-1) were given for intubation. Atracurium had a lower potency in anephric patients. The duration (first twitch response (TI) return to 20% of control) for atracurium was 28 min in anephric and 36 in normal patients. The corresponding mean times for pancuronium were 171 and 123 min, but with a very wide variation range 20-380 min and 45-360 min, respectively). The duration of up to 8 incremental doses of atracurium (0.1 mg kg-1) was 27-29 min in normal patients and of up to 13 increments was 25-34 min in anephric patients. Pancuronium (0.015 mg kg-1) was given in a maximum of 4 increments. In normal patients the mean durations were 40-56 min, and in anephric patients 65-100 min. The duration of pancuronium, but not of atracurium, was prolonged with repeated injections (up to 2.7 times) in anephric patients. After pancuronium the spontaneous recovery was significantly slower in anephric patients, while the induced recovery was rapid and reliable in all groups. We conclude that atracurium is a safe and reliable muscle relaxant in normal and anephric patients, while pancuronium in both groups has a disturbing variation in duration and, in addition, signs of significant accumulation in anephric patients. The use of a nerve stimulator is mandatory.

Adult↗