Clinical toxicology of propranolol and metoprolol overdose in adults

Beta-adrenergic receptor antagonists potentially risk causing fatal poisoning when taken over the daily recommended doses. The aim of this study is to investigate the differences and potential dose-related effects of propranolol and metoprolol toxicity depending on their selectivity. This 7-year-long retrospective cohort study was conducted among on 43 adult patients who received overdose propranolol (n= 22) and metoprolol (n= 21). Patients were divided into groups, with a daily overdose ≥ 240 mg/day for propranolol, ≥ 200 mg/day for metoprolol, and toxic dose ≥ 400 mg/day for both drugs. The groups were compared in terms of admission symptoms, heart rate, blood pressure, electrocardiography findings, cardiovascular effects, toxicity severity scores, treatment, follow-up times, and outcomes. Thirty-four (79.1%) of the patients who exceeded the daily dose were female, and there were no statistically significant differences between the groups in terms of gender (p= 0,281). The mean age was 29 (18-72) years, and there were no statistically significant differences between groups in terms of mean age (p= 0,192). When the vitals of the patients who exceeded the daily dose was examined, it was found that 23 (54.8%) patients had bradycardia, and 20 (46.5%) patients had hypotension. 65.2% of the bradycardia patients and 70% of the hypotensive patients were in the propranolol overdose group (p= 0,030 p= 0,021, respectively). Mean dose of symptomatic propranolol overdose patients (n= 12) was found as 1256 (280-2000) mg, mean dose of symptomatic metoprolol overdose patients (n= 11) was found as 559 (250-1000) mg. When toxic dose (≥ 400 mg) intakes were compared, more cardiovascular effects were observed in the propranolol group (p= 0,014). As a result, it was determined that Propranolol overdose has more cardiovascular effects than metoprolol overdose and there is a linear dose-symptom relationship for Propranolol.