Beta-Blocker Overdose

First Things First (assess & treat for the following)

• According to Poison Control Center for 2005, responsible for 60 deaths.
• Apply ABCs as appropriate; cardiac pacing or treatment with chronotrope/inotrope may be needed.
• Pathophysiology
  • Beta blockers inhibit calcium channel opening, resulting in hallmark toxicity of bradycardia, hypotension and conduction abnormalities.
  • They also antagonize sodium fast channels, causing QRS prolongation.
  • B1 subunit found in kidney, myocardium and eye. Blockade results in decreased conduction and contraction.
  • B2 subunit found in smooth muscle, skeletal muscle and pancreas. Blockade results in vasoconstriction, bronchospasm and hypoglycemia.
  • B3 subunit is involved in lipid metabolism.
  • Most beta blockers have peak effects in 1-4 hours; exceptions are extended-release preparations and sotalol.