An Interesting Case of Ingestion by Dr. Loran Hatch

Plaquenil (Hydroxychloroquine) Overdose
  • Small toxic to therapeutic window, 5g can lead to severe poisoning in adults
  • Clinical sx: abdominal pain, N/V/D, hypotension, apnea, dizziness, headache, convulsions  
  • Cardiotoxicity:
    • Sodium channel blockade -  QRS widening
    • Potassium channel blockade - QT prolongation
    • Can also see AV block, ST and T wave depression
    • Hypokalemia - due to intracellular shift - indicator of severity of overdose
  • Management: Aggressive supportive care
    • Consider early intubated and early activated charcoal
    • Fluid resuscitation
    • Epinephrine is the vasopressor of choice -Rec: 0.25 µg/kg/min increasing by 0.25 µg/kg/min until SBP > 90 mmHg
    • Diazepam - augments tx of dysrthythmias and hypotension
    • Also tx of seizures and for sedation
    • Sodium bicarb to correct wide QRS (goal 100ms) / Note can exacerbate hypokalemia
    • Permissive hypokalemia (consider repleting in severe hypokalemia). 
Barry J. Antimalarials. In: Hoffman RS, Howland M, Lewin NA, Nelson LS, Goldfrank LR. eds.Goldfrank's Toxicologic Emergencies, 10e New York, NY: McGraw-Hill; 2015