Histamine neuromuscular blocking drugs

Assem ES. Characteristics of basophil histamine release by neuromuscular blocking drugs in patients with anaphylactoid reactions. Agents Actions 1984 14(3 ) 435-40. 

Pancuronium Ls an aminosteroid neuromuscular blocking drug with a relatively long duration of action. It does not block ganglia or cause histamine release. However, it has a dose-related atropine-like effect on the heart that can produce tachycardia. 

Smith (1957) described cases of reactions to suxamethonium and other muscle relaxants, which occurred on the first exposure to these drugs, and therefore, could only be explained by direct histamine release. That many drugs or other chemicals can act as histamine releasers has been known for a long time (Paton 1957). The review by Paton (1957) included neuromuscular blocking drugs. However, the most relevant question which has not been answered so far is why should some patients react so adversely to those agents in the absence of evidence of allergy ... 

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. 

The autonomic margins of safety of the test drugs are calculated as the ratios of cumulative doses producing 50 % block (ED50) of vagal (parasympathetic) and sympathetic transmission and the ED50 for histamine release, each divided by the ED50 of neuromuscular blockade. 

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