Beta-blocker overdose

Learning objectives

Beta-blockers are a type of medicine used to treat high blood pressure and heart rhythm disturbances
Also used in the treatment of thyroid disease, migraine, and glaucoma
Isolated beta-blocker overdose is usually benign
Two beta-blockers require special consideration because of cardiac instability:
- Propanolol -> causes sodium channel blockade -> QRS widening -> treat with NaHCO3
- Sotalol -> causes potassium efflux blockade -> long QT -> monitor for Torsades
Beta-blockers competitively block beta-1 and beta-2 receptors
Results in decreased production of intracellular cyclic adenosine monophosphate (cAMP) with a resultant blunting of multiple metabolic and cardiovascular effects of circulating catecholamines
- In therapeutic doses, this leads to a reduced heart rate and blood pressure
- An overdose causes the heart to enter a shock state
Comorbid disease (CAD, CHF, atrial fibrillation, dysrhythmias, HOCM)

Respiratory system	Bronchospasm
Visual system	Blurred vision Double vision
Cardiovascular system	Hypotension Bradycardia AV block Heart failure
Metabolic system	Hypoglycemia Hyperkalemia
Nervous system	Weakness Nervousness Excessive sweating Drowsiness Confusion Seizures Fever Stupor Coma

beta-blocker overdose, bradycardia, propranolol, sotalol, activated charcoal, ECG, glucagon, insulin