Magnesium%2525252525252520sulphate

# Magnesium Sulphate ## Overview Magnesium sulphate is a parenteral mineral supplement and anticonvulsant. It acts as a calcium antagonist and reduces neuromuscular excitability. Pharmacokinetics are highly dependent on renal function. ## Primary Indications * **Eclampsia/Pre-eclampsia:** Seizure prophylaxis and treatment. * **Torsades de Pointes:** Acute management of polymorphic ventricular tachycardia. * **Severe Hypomagnesemia:** Replacement therapy. * **Severe Asthma:** Adjunct for status asthmaticus (non-responsive to standard therapy). ## Adult Dosing * **Eclampsia:** 4–6 g IV loading dose over 15–20 minutes, followed by 1–2 g/hr continuous infusion. * **Torsades de Pointes:** 1–2 g IV bolus over 5–20 minutes. * **Hypomagnesemia:** 1–4 g IV/IM. Severe deficiency may require 8–12 g over 24 hours. * **Severe Asthma:** 2 g IV bolus over 20 minutes (single dose). ## Pediatric Dosing * **Hypomagnesemia:** 25–50 mg/kg/dose IV/IM every 4–6 hours as needed (Max single dose: 2 g). * **Asthma:** 25–50 mg/kg IV over 20 minutes (Max single dose: 2 g). * *Note: Pediatric dosing depends heavily on local hospital protocols; verify institutional concentrations and infusion rates.* ## Dose Adjustments * **Renal Impairment:** Reduce dose in patients with renal insufficiency (CrCl < 30 mL/min). Monitor magnesium levels frequently. Avoid use in severe renal failure unless absolutely necessary. ## Contraindications * Heart block. * Myocardial damage. * Severe renal impairment (CrCl < 20 mL/min). * Hypocalcemia. ## Adverse Effects * **Common:** Flushing, sweating, hypotension, transient bradycardia. * **Severe (Magnesium Toxicity):** Loss of deep tendon reflexes (early sign), respiratory depression, heart block, cardiac arrest, CNS depression. ## Key Drug Interactions * **Neuromuscular Blockers:** Potentiates effect; monitor for prolonged paralysis. * **Aminoglycosides:** Increased risk of neuromuscular blockade. * **Calcium Channel Blockers:** Risk of severe hypotension and potentiated cardiac effects. * **Digoxin:** Use caution; sudden shifts in serum magnesium can precipitate digitalis toxicity. ## Monitoring * **Clinical:** Check patellar reflexes (loss usually occurs at serum Mg > 10 mg/dL), respiratory rate (must be > 16 breaths/min), and urine output (must be > 30 mL/hr). * **Laboratory:** Serum magnesium concentrations (Target: 4–8 mg/dL in eclampsia; 1.5–2.5 mg/dL normal range for maintenance). * **Cardiac:** Continuous ECG monitoring during rapid IV administration for arrhythmia. ## Clinical Pearls * **Antidote:** Keep Calcium Gluconate (1 g IV) at the bedside at all times to reverse respiratory depression or cardiac toxicity. * **Administration:** Rapid IV bolus can cause hypotension and asystole. Use infusion pumps for all continuous doses. * **Renal Caution:** Magnesium is renally excreted; monitor serial electrolyte levels in any patient with decreased renal function to avoid accumulation. *** *Disclaimer: This information is for educational purposes only. Clinical practices vary by institution. Always consult your institutional protocols, formulary, and official product labeling (e.g., package inserts) before prescribing or administering medication.*