II. Pathophysiology
- Beta Blocker Overdose is treated the same as Calcium Channel Blocker Overdose
- Selective Beta Blockers lose selectivity in Overdose
- Overdosed Beta Blockers affect all receptors regardless of whether agent is beta-1 or beta-2 selective
- Mechanism
- Inhibits fast Sodium channels with decreased contractility and Hypotension, in addition to Bradycardia
- Beta-2 blockade results in bronchoconstriction and Hypoglycemia
III. Precautions
- Beta Blocker Overdoses are high risk of death (on par with Tricyclic Antidepressants and Calcium Channel Blockers)
- Treat at similar intensity as a full code as these patients decompensate rapidly
IV. Symptoms and Signs
- Primary toxic effects
- Other effects
- Acidosis
- Bronchospasm
- Coma
- Hypoglycemia (esp. in children)
- Contrast with Hyperglycemia in Calcium Channel Blocker Overdose
- Hyperkalemia
- Respiratory depression
- Lipophilic Beta Blockers (primarily Propranolol, but also Metoprolol and Pindolol)
V. Management
- See Calcium Channel Blocker Overdose for management
- Expect a rapid decompensation after ingestion (2 hours)
- Specific concerns with Beta Blocker Overdose (contrast with Calcium channel Overdose)
- Glucagon
- Appears more effective in Beta Blocker Overdose than in Calcium Channel Blocker Overdose
- See Calcium Channel Blocker Overdose for dosing, mechanism and protocols
- Hypoglycemia
- Inhibited Beta-2 Adrenergic Receptors (Gluconeogenesis, Glycolysis inhibited by blockade)
- Monitor Glucose every 30 min (more often if on euglycemic Insulin protocol)
- Start D10 if Glucose is trending downward
- Glucagon
VI. References
- Yen (2015) Crit Dec Emerg Med 29(10): 18-23
- Anderson (2008) Clin Pediatr Emerg Med 9(1): 4-16 [PubMed]
- Kerns (2007) Emerg Med Clin North Am 25(2):309-31 [PubMed]