Is Beta Blocker Toxicity Associated With Hypoglycemia?

INTRODUCTION

It is commonly taught that beta blocker toxicity is associated with development of hypoglycemia, however, empirical evidence is lacking. We aimed to evaluate the association of beta blocker toxicity with hypoglycemia.

METHODS

We performed a retrospective cohort study of cases reported to a regional poison center from 1/1/2018 to 1/1/2025. Beta blocker toxicity was defined as cases coded as beta blocker exposure with documented bradycardia. Cases of acetaminophen or selective serotonin reuptake inhibitor (SSRI) overdose were selected as controls. Primary outcome was development of hypoglycemia defined as glucose concentration less than 70 mg/dL. A pre-planned subgroup analysis was performed for all groups, comprised of patients meeting the following criteria: single substance exposures, no documented diabetes, and no documented insulin administration. Descriptive statistics were performed, and relative risk for hypoglycemia was calculated between beta blocker and control groups.

RESULTS

There were 225 cases that met inclusion criteria for beta blocker toxicity, with 1,586 acetaminophen cases, and 1,955 SSRI cases included as controls. The relative risk of hypoglycemia for beta blockers compared to acetaminophen at any time was 1.44 (95% CI: 0.74, 2.80; p = 0.38) and 1.74 (95% CI: 0.89, 3.38; p = 0.15) compared to SSRI. No differences were identified between groups when evaluating the initial presenting glucose or in the pre-planned subgroup analysis.

CONCLUSIONS

There was no significantly increased risk of hypoglycemia in beta blocker poisoned patients compared to controls. This suggests that hypoglycemia would not be an expected finding in beta blocker toxicity.