Magnesium%25252525252525252525252525252525252520sulphate

# Magnesium Sulphate ## Overview Magnesium sulphate is a parenteral mineral supplement used primarily for severe hypomagnesemia, eclampsia, and torsades de pointes. It acts as a calcium antagonist and reduces acetylcholine release at the neuromuscular junction. ## Primary Indications * **Obstetric:** Prevention/control of seizures in pre-eclampsia/eclampsia. * **Cardiac:** Torsades de pointes, life-threatening ventricular arrhythmias (refractory). * **Metabolic:** Symptomatic severe hypomagnesemia. * **Respiratory:** Acute severe asthma exacerbation (adjunctive therapy). ## Adult Dosing * **Torsades de pointes:** 1–2 g IV push over 5–20 minutes; may repeat once if needed. * **Eclampsia/Pre-eclampsia:** Loading dose 4–6 g IV over 15–20 minutes, followed by maintenance infusion of 1–2 g/hour. Follow institutional protocols strictly. * **Hypomagnesemia (severe/symptomatic):** 1–4 g IV over 1–4 hours. Dose depends on severity; repeat as needed based on serum magnesium levels. * **Acute Asthma:** 2 g IV over 20 minutes (single dose). ## Pediatric Dosing * **Hypomagnesemia:** 25–50 mg/kg/dose IV over 1–4 hours; may repeat every 6 hours as needed. * **Asthma:** 25–75 mg/kg IV (max 2 g) over 20 minutes (single dose). * *Note: Consult pediatric references (e.g., Harriet Lane) for specific age-based weight dosing.* ## Dose Adjustments * **Renal Impairment:** Reduce dose in patients with renal insufficiency (CrCl <30 mL/min). Magnesium is cleared renally; risk of toxicity is high. Max dose typically 20 g/48 hours in renal impairment. ## Contraindications * Myasthenia gravis. * Heart block (unless pacemaker present). * Severe renal impairment (CrCl < 20 mL/min—use with extreme caution). * Myocardial tissue damage. ## Adverse Effects * **Neuromuscular:** Loss of deep tendon reflexes (DTRs). * **Cardiac:** Hypotension, bradycardia, cardiac arrest (high doses). * **Respiratory:** Respiratory depression. * **Other:** Flushing, sweating, hypothermia, infusion site pain. ## Key Drug Interactions * **Neuromuscular Blockers:** Potential for significantly enhanced neuromuscular blockade. * **Aminoglycosides/Calcium Channel Blockers:** Increased risk of potentiation of neuromuscular/cardiovascular effects. * **Digoxin:** Potential for arrhythmias if magnesium levels shift rapidly. ## Monitoring * **Serum Magnesium:** Check levels every 4–6 hours (or per protocol). * **Reflexes:** Monitor DTRs (patellar) hourly (absence suggests toxicity). * **Respiratory:** Monitor rate/effort; hold if <12 breaths/min. * **Renal:** Monitor urine output (maintain >0.5 mL/kg/hour). * **Toxicity Treatment:** **Calcium gluconate** (1 g IV over 5–10 minutes) is the antidote for magnesium toxicity. ## Clinical Pearls * **Safety:** Always verify concentration (e.g., 10%, 50%). 50% solution is hypertonic and must be diluted for IV infusion. * **Administration:** Rapid IV push can cause profound hypotension or asystole. * **Local Protocols:** Eclampsia dosing varies significantly by institution; strictly adhere to local standard orders. *** *Disclaimer: This information is for educational purposes and does not replace medical judgment. Always verify current dosing guidelines, compatibility, and institutional protocols before prescribing or administering medication.*