PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Neuromuscular Blocking Agents”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1991

Clinical pharmacology of the neuromuscular blocking agents.

Neuromuscular blocking agents are among the most commonly used drugs during general anesthesia. They compete with acetylcholine and interfere with the transmission of nerve impulses resulting in skeletal muscle relaxation. Based on their mechanism of action, neuromuscular blocking agents are classified as either depolarizing or nondepolarizing. Succinylcholine is a short-acting depolarizing agent. Commonly used nondepolarizing agents are curare (long-acting), pancuronium (long-acting), atracurium (intermediate-acting), and vecuronium (intermediate-acting). Neuromuscular blocking agents are used clinically to facilitate endotracheal intubation and to provide skeletal muscle relaxation during surgery. This article provides an overview of the physiology of the neuromuscular transmission and summarizes our current knowledge on the use of these agents during general anesthesia.

Atracurium↗
PubMed1992

Disadvantages of neuromuscular blocking agents.

Neuromuscular blocking agents have few indications and significant contraindications or problems associated with their use. The need for controlled ventilation and the difficulties of monitoring anesthetic depth when using neuromuscular blocking agents are overriding factors that mitigate against their routine use.

Anesthesia↗
PubMed1984

Experimental and clinical evaluation of neuromuscular blocking agents.

Neuromuscular blocking agents can be evaluated in anesthetized cats, dogs, or rhesus monkeys using dose-response relationships to assess the degree of separation between neuromuscular blocking activity and effects on cardiovascular and autonomic systems. Histamine release can be studied in anesthetized dogs by establishing whether any induced hypotension is reduced by pretreatment with H1 and H2 receptor antagonists. In anesthetized cats, the role of the liver in metabolism is investigated after administration of the drug by the hepatic portal vein and determining whether this "first pass" effect through the liver reduces potency. The involvement of the kidneys in the elimination of the drug can be assessed by ascertaining whether or not the potency and duration of action are enhanced after bilateral renal ligation. In anesthetized man, the simultaneous measurement of the tetanic (50 Hz) and single twitch contractions of the adductor pollicis muscle of the hand has proved a valuable technique for the quantitative assessment of skeletal muscle relaxants. Furthermore, the tetanic response overcomes the relative insensitivity of the single twitch, and tetanic fade provides a measure of the effects of these drugs at presynaptic sites. Cumulative effects may be evident as a prolonged recovery after repeated dosage or after an infusion. The effectiveness of neostigmine as an antagonist should be investigated both from partial and complete block, and recovery of respiration should be compared with that of peripheral neuromuscular blockade.

Animals↗
PubMed1992

Advantages of and guidelines for using neuromuscular blocking agents.

Neuromuscular blocking agents, although not commonly used in veterinary practice, should be considered when muscle relaxation is needed to facilitate surgical exposure and minimize tissue trauma. These drugs should be administered only once respiration has been controlled and anesthetic agents have been administered to induce unconsciousness and analgesia. Following administration of neuromuscular blocking drugs, neuromuscular and cardiovascular function must be monitored.

Adjuvants, Anesthesia↗
PubMedDate not supplied

System improvements for the use of neuromuscular blocking agents.

Neuromuscular blocking agents (NMBA) are commonly used in the emergency department, operating room, and intensive care unit. After two separate incidents in which NMBA were not immediately available in an emergency, a quality assurance process was used to identify the method for controlling distribution and availability of NMBA use in the emergency department. The new system uses a pharmacy-stocked paralytic agent box and transport bag. The benefits of this system have included (1) 100% availability of NMBA when needed in the emergency department, (2) better availability of supplies and ease in transporting for times when a patient needs to be moved within the hospital, and (3) more efficient billing and tracking of controlled substances by the pharmacy department.

Adolescent↗
PubMed1994

Persistent paralysis in critically ill patients after the use of neuromuscular blocking agents.

Neuromuscular blocking agents (NMBAs), an important part of the pharmacologic armamentarium of the intensivist, have a long and admirable history of safety when used in the operating room for periods of time (almost always < 12 hrs). Since 1985, dozens of medical journals have reported a multitude of studies on persistent paralysis when these same agents are exported from the operating room to the ICU. Most of these reports are case presentations of patients who failed to move for days to weeks after discontinuation of NMBAs. These reports have led to concern about the appropriate use of NMBAs in the ICU. This article sorts through the issues surrounding persistent paralysis, and defines it as a short-term and a long-term problem. The short-term problem seems to have a pharmacologic explanation that is not difficult to correct. The long-term problem is much more complex and may have a toxic explanation that may also be more difficult to manage.

Critical Care↗
PubMedDate not supplied

An algorithm for train-of-four monitoring in patients receiving continuous neuromuscular blocking agents.

Neuromuscular blocking agents (NMBA) are increasingly being used in the management of critically ill patients. These medications are used to facilitate mechanical ventilation. Strange and colleagues estimated that only 4% of intensive care units utilize train-of-four (TOF) monitoring on a regular basis and that 70% never use this type of monitoring. The ease of use and low cost of the equipment lends itself to the increasingly frequent recommendations for this type of monitoring. Although unwilling to go so far as to establish this as a standard of care, the American College of Critical Care Medicine of the Society of Critical Care Medicine released an executive summary recommending train-of-four monitoring for patients receiving continuous or sustained NMBAs. This protocol and algorithm was developed to facilitate the objective monitoring of patients receiving continuous NMBAs.

Electric Stimulation↗
PubMed2004

Adverse reactions to neuromuscular blocking agents.

Neuromuscular blocking agents (NMBAs) play a predominant role in the incidence of severe adverse reactions occurring during anesthesia. Most hypersensitivity reactions are of immunologic origin (IgE-mediated) or are related to direct stimulation of histamine release. The incidence of IgE-mediated hypersensitivity or anaphylaxis is estimated between 1 in 10,000 and 1 in 20,000 anesthesias, and NMBAs represent the most frequently involved substances, with a range of 50% to 70%. Any suspected anaphylactic reaction must be extensively investigated using combined perioperative and postoperative testing. Because of the frequent cross-reactivity observed with muscle relaxants, every available NMBA should be tested. This should help provide documented advice for future administration of anesthesia. There is no demonstrated evidence for systematic preoperative screening in the general population at this time. Other well-known adverse effects have been described, such as the succinylcholine-triggered cytotoxic effects on muscle cells, but these are responsible for characteristic clinical symptoms, which are usually easy to distinguish from anaphylactic reactions

Anaphylaxis↗
PubMed1994

Newer neuromuscular blocking agents.

Four neuromuscular blocking drugs, doxacurium, mivacurium, pipecuronium, and rocuronium have been or are about to be introduced into clinical practice. The purpose of this MiniReview is to describe their pharmacology, to consider their place in clinical anaesthetic practice, and to examine whether the needs of the clinician have been met. Two of the agents (doxacurium, mivacurium) are benzylisoquinolines resembling atracurium and two (pipecuronium, rocuronium) are aminosteroids related to pancuronium and vecuronium. Two (doxacurium, pipecuronium) are long-acting compounds, similar in duration of action to pancuronium, although the need for such a profile is questionable. Rocuronium has an intermediate duration of action and produces its maximum effect within two minutes which is much more rapid than any other non-depolarizing relaxant and this is probably a result of its poor potency. However, the onset of paralysis is not as quick as after succinylcholine. Mivacurium is unique because it is metabolized by plasma cholinesterase which produces a rapid recovery although slower than succinylcholine. All of the new drugs are devoid of serious cardiovascular or other side effects. The anaesthetist is now presented with an armamentarium of safe, nondepolarizing muscle relaxants with varying durations of action. However, the rapid onset and recovery associated with succinylcholine are unique and important in the urgent control of a patient's airway and respiration. The indications for succinylcholine will not disappear and the search for a non-polarizing replacement will continue.

Androstanols↗
PubMed1999

Clinical pharmacology of neuromuscular blocking agents.

The clinical pharmacology of neuromuscular blocking agents is described. During neuromuscular blockade, succinylcholine attaches to receptors in the motor end plate and depolarizes the neuromuscular junction, making the end plate refractory to acetylcholine. The nondepolarizing relaxants have a structure similar to that of succinylcholine and bind to the same receptors. Instead of depolarizing the junction, they block acetylcholine from binding to the receptor and cause channel blockade. As the concentration of nondepolarizing relaxant increases relative to acetylcholine, neuromuscular transmission is compromised. This relationship is used clinically to facilitate recovery from nondepolarizing agents. Succinylcholine is popular because its onset is faster than that of the nondepolarizing relaxants and metabolism by pseudocholinesterase clears it quickly. It is commonly given as an i.v. bolus to facilitate tracheal intubation. The onset of these agents varies widely and is dose dependent. Large doses are usually given to hasten the onset of paralysis; subsequent doses are adjusted according to response. The nondepolarizing agents interact with inhaled anesthetics, magnesium, and many antimicrobials. Drugs like neostigmine, edrophonium, and pyridostigmine antagonize neuromuscular blockade; an anticholinergic drug is typically administered to counteract the cardiovascular effects. The most serious adverse effects of succinylcholine are malignant hyperthermia syndrome, masseter muscle rigidity, and bradycardia. Some nondepolarizing relaxants (atracurium, mivacurium, and pancuronium) are associated with histamine release, occasionally causing serious hypotension and tachycardia. Neuromuscular blocking agents are essential to anesthesia. Older compounds produce greater toxicity than newer compounds, and several of these older compounds therefore are no longer in clinical use.

Drug Interactions↗
PubMed2000

Why should I change my practice of anaesthesia: neuromuscular blocking agents.

BACKGROUND: Recently, four neuromuscular blocking agents have been introduced into clinical practice. The drug companies claim that these new drugs offer several important advantages. But is this true? Do the new neuromuscular blocking agents add anything to our clinical practice, and will their introduction really benefit our patients? Or will it only benefit the economy of the companies? PURPOSE OF THE LECTURE: In this lecture I shall try to update you on these new drugs and give you my personal bias on when to use the different (new and old) neuromuscular blocking agents.

Anesthesia↗
PubMed1993

Neuromuscular blocking agents in critical care.

Neuromuscular blocking agents have been used in critically ill patients for over 30 years. Recently, the pharmacology, monitoring, and toxicity of these agents have received much attention. This article reviews the pharmacology, indications, monitoring parameters, and toxicity of the neuromuscular blocking agents commonly used in the intensive care unit.

Critical Care↗
PubMed1958

Effects of rate of stimulation and of fatigue on the response to neuromuscular blocking agents.

The response to neuromuscular blocking agents, as exemplified by suxamethonium and tubocurarine, may differ between symmetrical muscles. Increased rates of stimulation and fatigue both increase sensitivity to blocking agents. During recovery from suxamethonium block muscles may show a transitory failure to react to each stimulus with a contraction. Fatigue caused by prolonged indirect stimulation is prevented equally well by suxamethonium and tubocurarine in doses producing a complete block. The mechanism and significance of these findings are discussed.

Fatigue↗
PubMed1999

Neuromuscular blocking agents in paediatric anaesthesia.

Neuromuscular blocking agents are used commonly in paediatric anaesthesia, both to facilitate tracheal intubation and during surgery. Paediatric patients differ from adults in certain pharmacokinetic and pharmacodynamic characteristics. However, because maturational changes in certain of these characteristics counterbalance, dosing requirements do not differ markedly with age. In general, onset is more rapid in paediatric patients than in adults. Succinylcholine is still used commonly in children, despite restrictions by regulatory authorities, because of its rapid onset and offset. However, newer non-depolarizing neuromuscular blocking agents, particularly mivacurium, rocuronium and rapacuronium, offer many of the advantages of succinylcholine without its severe adverse effects: rocuronium and rapacuronium have an onset comparable with that of succinylcholine whereas the onset of mivacurium is slightly longer. In addition, recovery from an intubating dose of either mivacurium or rapacuronium is nearly comparable with that of succinylcholine. If rapacuronium i.m. proves to have a rapid onset without prolonged duration, the remaining value of succinylcholine will diminish.

Adult↗
PubMed2002

Synthesis and structure-activity relationships of neuromuscular blocking agents.

The first use of neuromuscular blocking agents (muscle relaxants) in clinical practice (1942) revolutionised the practice of anaesthesia and started the modern era of surgery. Since 1942 introduction of tubocurarine (18) neuromuscular blocking agents have been used routinely to provide skeletal muscle relaxation during surgical procedures allowing access to body cavities without hindrance from voluntary or reflex muscle movement. After the introduction of tubocurarine and the depolarizing suxamethonium chloride (4) (1949) several nondepolarizing steroidal and nonsteroidal neuromuscular blocking agents with different onset time and duration of effect were introduced e.g. gallamine triethiodide (1) (1949), methocurine (2) (1949), alcuronium chloride (3) (1963), pancuronium bromide (9) (1968), vecuronium bromide (11) (1982), pipecuronium bromide (10) (1982), atracurium besylate (5) (1982), doxacurium chloride (6) (1991), mivacurium chloride (8) (1992), rocuronium bromide (12) (1994) cisatracurium besylate (7) (1996), and rapacuronium bromide (13) (2000). SZ 1677 (14) a steroid type nondepolarizing neuromuscular blocking agent under development (preclinical phase). This review article deals with a comprehensive survey of the progress in chemical, pharmacological and, in some respects, of clinical studies of neuromuscular blocking agents used in the clinical practice and under development, including the synthesis, structure elucidation, pharmacological actions, structure activity relationships studies of steroidal and nonsteroidal derivatives.

Androstanes↗
PubMed2000

Does monitoring of post-tetanic count prevent alarms of airway pressure or visible muscle activity during intratracheal jet ventilation? A prospective study with five different neuromuscular blocking agents.

OBJECTIVE: Profound neuromuscular block (NMB) quantified by post-tetanic count (PTC) may prevent all muscle activity during anesthesia. We studied whether monitoring of PTC prevents airway pressure alarms or visible movements of the vocal cords and the abdomen during endolaryngeal procedures (ELPs). METHODS: In this prospective, double blind, study 50 healthy (ASA 1-3) patients scheduled for ELPs were randomized into five groups: atracurium, mivacurium, rocuronium, vecuronium and succinylcholine. During alfentanil-propofol anaesthesia, profound NMB was controlled by monitoring the PTC (target level PTC 0-2, 50 Hz tetanic stimulation) of the adductor pollicis muscle. The muscle relaxants were administered using bolus dosing in all groups but in the succinylcholine group. The early signs of recovery of NMB to be observed were: 1) airway pressure alarms, 2) movements of vocal cords on the laryngeal video monitor and 3) movements of the abdomen. The inference was based on 90% confidence interval tests. RESULTS: During 50 ELP:s following signs of early recovery of NMB were recognized: 2 alarms of airway pressure, 16 laryngeal movements and 11 movements of the abdomen. The proportion of airway pressure alarms was significantly lower than proportion of all detectable movements (95% confidence interval analysis). Twelve of the movements were recorded at PTC zero level. The signs of early recovery of NMB were detected in all groups. CONCLUSIONS: PTC-monitoring following 50 Hz stimulation does not ensure total inactivity of muscles during alfentanil-propofol anesthesia, regardless which relaxant has been chosen. During ELPs, simultaneous observation of the vocal cords and the abdomen is more sensitive in detecting early recovery of NMB compared to our method of airway pressure monitoring.

Abdomen↗
PubMed1997

Neuromuscular transmission and its pharmacological blockade. Part 2: Pharmacology of neuromuscular blocking agents.

Clinically, neuromuscular blockade is induced with either depolarizing or non-depolarizing relaxants. Suxamethonium is the only depolarizing relaxant still in use. It is hydrolysed in the plasma by pseudo-cholinesterase (plasma cholinesterase). In some patients and in particular diseases the plasma cholinesterase activity is low and hence the effect of suxamethonium prolonged. Suxamethonium is characterized by side-effects such as myalgia, fasciculations and increase in intraocular, intracranial and intragastric pressure. More serious adverse reactions are masseter muscle spasm and potassium release, in patients with some neuromuscular diseases and increase in extrajunctional acetylcholine receptors. As non-depolarizing muscle relaxants benzylisoquinolines and steroidal compounds are mainly used. Each relaxant has its own pharmacological characteristics. The effect of most relaxants depends on liver and renal function because the pharmacokinetic behaviour is strongly dependent on these organs. Also, acid base balance disturbances, change in temperature, and neurological diseases have an effect on the profile of the relaxants. A number of drugs (anaesthetics, antibiotics, antiepileptics, etc.) have an effect on neuromuscular transmission, and thus interact with the relaxants. Some non-depolarizing relaxants cause histamine release and cardiovascular effects.

Body Temperature↗