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