Pancuronium and Histamine release

Some neuromuscular blocking agents stimulate the release of histamine, which can cause wheezing, bronchospasm, increased bronchial secretions, hypotension, tachycardia, and circulatory collapse. Hypotension may also occur due to ganglionic blockade or as a complication of positive pressure respiration. Tubocurarine appears to be the most potent inducer of histamine, followed by metocurine (no longer commercially available in the U.S.) and succinylcholine. Other agents with varying but lesser degrees of histamine-releasing properties include atracurium, mivacurium, and pancuronium (at excessive dosages). Therapy with these neuromuscular blocking agents should be administered cautiously in patients with clinically significant cardiovascular disease and/or a history of asthma or severe allergic reactions. Certain agents may prolong the QTc interval, especially during general anesthesia in pediatric patients. The initial dosage and rate of administration may need to be reduced, and hemodynamic and respiratory status carefully monitored. Neuromuscular blocking agents that appear to have little or no histamine-inducing effects include cisatracurium, doxacurium, pipecuronium, rocuronium, and vecuronium.