Neuromuscular blocking agent

Agents that block the transmission of ACh at the motor end plate are called neuromuscular blocking agents. The therapeutic use of these compounds is primarily as adjuvants in surgical anesthesia to obtain relaxation of skeletal muscle. They also are used in various orthopedic procedures, such as alignment of fractures and correction of dislocations. 

The po.ssible existence of a junction between muscle and nerve was suggested as early as 1856, when Claude Bernard ob.servcd that the site of action of curare was neither the nerve nor the muscle. Since that lime, it has been agreed that ACh mediates transmission at the neuromuscular junction by a sequence of events described above in this chapter. The neuromuscular junction consists of the axon impinging onto a specialised area of the mu.scle known as the muscle end plate. The axon is covered with a myelin sheath, containing the nodes of Ranvier, but is bare at the ending. The nerve terminal is separated from the end plate by a gap of 200 A. The subsynaptic membrane of the end plate contains the cholincigic receptor, the ion-conducting channels (which are opened under the influence of ACh), and AChE. 

Ihe untagonist compete on a one-to-one basis for the end plate receptors. Drugs in this class are tubocurarine, dimeth-yltub x ururinc. pancuronium, and gallaminc. 

Originally curare was a term used to describe collectively the very potent arrow poisons used since early times by the South American Indians. The arrow poisons were prepared from numerous botanic sources and often were mixtures of several different plant extracts. Some were poisonous by virtue of a convulsant action and others by a paralyzant action. Only the latter type is of value in therapeutics and is spoken of ordinarily as curare. 

Tubocurarine Chloride, USP. Tubocurarine chloride. (+ )-tubocurarinc chloride hydrochloride pentahydratc. is prepared from crude curare by a process of purification and crystallization. Tubocurarine chloride occurs as a white or 

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C14H30CI2N2O4. White powder prepared from dimethylaminoethanol and succinyl chloride, followed by methylation. Neuromuscular blocking agent used to relax skeletal muscles during certain types of surgical operation. 

Adverse effects of neuromuscular blocking agents 10 based on yellow card reporting in the UK. Are there differences between males and females Pharma-coepidemiol Drug Saf 2006 15 151. 

Pholcodine exposure raises serum IgE in patients 30 with previous anaphylaxis to neuromuscular blocking agents. Allergy 2007 62 1445. 

Mertes PM, Moneret-Vautrin DA Skin reactions to intradermal neuromuscular blocking agent injections a randomized multicenter trial in healthy volunteers. Anesthesiology 2007 107 245. Moneret-Vautrin DA, Gueant JL, Kamel L, Laxenaire MC, el Kholty S, Nicolas JP Anaphylaxis to muscle relaxants cross-sensitivity studied by radioimmunoassays compared to intradermal tests in 34 cases. J Allergy Clin Immunol 1988 82 745. 

Contrary to other elicitors of non-immune anaphylactic reactions (radiocontrast media, neuromuscular blocking agents, non-steroidal anti-inflammatory drugs (NSAIDs)) where there are at least hypothetical concepts regarding the pathomecha-nism of these reactions via increased mediator release (e.g. histamine release, shift in arachidonic acid metabolism from prostaglandins towards leukotrienes, etc.) [26], there is almost no literature regarding the pathomechanism of these reactions after LA application. 

Dunlap J, Brown JH. Heterogeneity of binding sites on cardiac muscarinic receptors induced by the neuromuscular blocking agents gallamine and pancuronium. Mol Pharmacol 1983 24 15-22. 

Colquhoun, D., On the principles of postsynaptic action of neuromuscular blocking agents, in New Neuromuscular Blocking Agents, Kharkevich, D. A., Ed., Springer-Verlag, Berlin/New York, 1986. 

Aminoglycosides Neuromuscular blocking agents Additive adverse effects Avoid... 

Sparr, H.J., Beaufort, T.M. and Fuchs-Buder, T. (2001) Newer neuromuscular blocking agents how do they compare with establishes agents Drugs, 61, 919-942. 

Demonstrate the two clusters with the same time separation. In the presence of a neuromuscular blocking agent, the second cluster will have a lesser amplitude than the first (70% is shown). 

The above and reports from other workers (awaiting publication at the time of writing), strongly suggest that this type of neuromuscular blocking agent constitutes a notable advance in anaesthesia. The properties of pancuronium, which make it of special value in the poor-risk or asthmatic patient may be briefly summarized as ... 

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