Recognize
- 4–6: nausea, flushing, headache, ↓ DTRs
- 6–10: somnolence, hypotension, loss of DTRs, bradycardia, EKG changes (PR/QRS prolong)
- > 10: respiratory paralysis, complete heart block, asystole
- Causes: renal failure + Mg load (eclampsia tx, antacids, laxatives, enemas)
Stop Mg + antagonize
- Stop all Mg sources (IV, antacids, cathartics)
- Calcium gluconate 1–2 g IV over 5–10 min — direct antagonist for cardiac/neuromuscular toxicity
- Repeat calcium PRN for symptoms
Enhance elimination
- NS + furosemide 20–40 mg IV — if renal function adequate
- Hemodialysis: severe symptoms, renal failure, refractory
Supportive
- Airway support / intubation for respiratory paralysis
- Pacing / atropine for symptomatic bradycardia or block
- Vasopressors for hypotension refractory to fluids
Disposition
- Admit all symptomatic · ICU for cardiac or respiratory involvement