Poisoning patients’ clinical features according to the blood level of propranolol

Purpose: Propranolol is widely prescribed to psychiatric patients to control adrenergic symptoms. However, propranolol poisoning can be fatal due to cardiovascular complications. We analyzed associations between blood levels of propranolol and patients’ clinical features, with the aim of predicting progression to severe complications.Methods: Data were collected from patients aged 18 years or older who presented to the emergency department with propranolol poisoning between January 2016 and May 2022. We retrospectively analyzed their medical records and compared blood levels of propranolol between those who had cardiovascular complications and those who did not.Results: Two hundred patients were included in this study. The blood levels of propranolol were significantly higher in patients with hypotension, bradycardia, and prolonged QT intervals, with median values of 247.0 ng/mL (interquartile range [IQR], 56.5–333.8 ng/mL), 275.8 ng/mL (IQR, 154.3–486.4 ng/mL), and 159.0 ng/mL (IQR, 33.9–310.8 ng/mL), respectively. In the predictive analysis of cardiovascular complications using a receiver operating characteristic curve, the area under the curve was 0.729 with a cut-off value of 72.40 ng/mL (sensitivity, 0.667; specificity, 0.819). In addition, the correlation coefficient between blood levels and the amount of drug described during the history-taking at the time of presentation was 0.634, which was found to have a significantly higher relationship.Conclusion: Because blood levels of propranolol can be used as predictors of exacerbation in patients with propranolol poisoning, patients with blood levels above 72.40 ng/dL require careful treatment and observation from their initial presentation at the emergency department.