Allergy to muscle relaxants: diagnosis and significance of drug concentrations

Abstract Objectives Allergic reactions to muscle relaxants are a major cause of perioperative anaphylaxis. This study aimed to evaluate how plasma concentrations of muscle relaxants, genetic predispositions, and immunometabolic changes influence the risk and severity of hypersensitivity reactions to improve diagnostic accuracy and support personalised perioperative management. Methods A total of 120 adult patients undergoing general anaesthesia were examined using intradermal testing, ELISA-based assays for specific IgE, basophil activation tests, cytokine profiling, plasma drug concentration measurements (HPLC–MS), molecular genetic analysis of IL-4 and IL-13 polymorphisms, and proton magnetic resonance spectroscopy for metabolic profiling. A control group (n=60) underwent parallel testing. Statistical evaluation included correlation analysis, logistic regression, and ROC curve assessment. Results Positive allergic reactions were observed in 15.8 % of patients, most commonly to atracurium (9.2 %). Patients with positive reactions showed significantly higher plasma concentrations of atracurium (2.8 ± 0.4 μg/mL vs. 1.7 ± 0.3 μg/mL; p