Peri‐operative hypersensitivity reactions to neuromuscular blocking drugs in New Zealand 2013–2019: a retrospective observational study

Summary Introduction Peri‐operative hypersensitivity reactions are rare and unpredictable events that can result in significant patient harm. Neuromuscular blocking drugs are one of the leading causes of peri‐operative hypersensitivity reactions in many parts of the world. Methods Our retrospective observational cohort study of in adults in New Zealand investigated the incidence and relative risk of a peri‐operative hypersensitivity reaction to the various to neuromuscular blocking drugs. We also explored possible cross‐sensitivity between the different neuromuscular blocking drugs using skin testing. The incidence of anaphylaxis to neuromuscular blocking drugs was calculated within a subset of our cohort, using confirmed cases of anaphylaxis to each neuromuscular blocking drug as the numerator and number of new patient exposures to the drug as the denominator. Results We determined the risk of a peri‐operative hypersensitivity reaction with individual neuromuscular blocking drugs to be: suxamethonium 1:1500 (95%CI 1000–2500); rocuronium 1:3300 (95%CI 2100–5300); and atracurium 1:15,000 (95%CI 6800–40,000). Female patients were up to eight times more likely to experience a peri‐operative hypersensitivity reaction than males. Our skin test results suggest that if a patient experiences a peri‐operative hypersensitivity reaction to rocuronium, suxamethonium or vecuronium, then atracurium is the lowest risk alternative. If a patient has had a peri‐operative hypersensitivity reaction to atracurium, then rocuronium and suxamethonium are low risk alternatives. Discussion We found a significant difference between the rates of peri‐operative hypersensitivity reactions with rocuronium and suxamethonium vs. atracurium. The increased risk of a peri‐operative hypersensitivity reaction is a factor that should be weighed against the benefits of using suxamethonium or rocuronium. Females may be higher risk than males of reacting to neuromuscular blocking drugs.