Magnesium%252525252525252525252525252525252525252525252525252525252525252525252520sulphate

# Magnesium Sulphate ## Overview Magnesium sulphate is an electrolyte that plays a crucial role in various biochemical processes. It is available in intravenous (IV) and intramuscular (IM) formulations. ## Primary Indications * **Eclampsia/Preeclampsia:** Treatment and prevention of seizures in severe preeclampsia and eclampsia. * **Hypomagnesemia:** Treatment of magnesium deficiency. * **Torsades de Pointes:** Treatment of polymorphic ventricular tachycardia. * **Bronchodilator:** Adjunctive therapy in severe asthma exacerbations. ## Adult Dosing * **Eclampsia/Preeclampsia:** * **Loading Dose:** 4-6 g IV infused over 5-20 minutes. * **Maintenance Dose:** 1-2 g/hour IV infusion. Alternatively, 5 g IM into each buttock (10 g total) followed by 5 g IM every 4 hours as needed. Dosing protocols can vary significantly by institution. * **Hypomagnesemia:** * **Severe Deficiency:** 4 g IV infused over 5-60 minutes, followed by 1-2 g/hour infusion. * **Less Severe Deficiency:** 1-2 g IV infused over 5-60 minutes, or 1 g IM every 4 hours for 4 doses. * **Torsades de Pointes:** 1-2 g IV diluted in 10 mL D5W, infused over 5-10 minutes. Additional doses of 1-2 g can be given as a continuous infusion. * **Asthma Exacerbation:** 1-2 g IV infused over 15-30 minutes. ## Pediatric Dosing Dosing is weight-based and protocols vary. Specific pediatric guidelines should be consulted. * **Hypomagnesemia:** Generally, 25-50 mg/kg/dose IV every 4-6 hours. Maximum dose usually around 2 g. ## Dose Adjustments * **Renal Impairment:** Magnesium sulphate is renally excreted. Use with caution in renal impairment; dose reduction and close monitoring of magnesium levels are necessary. Avoid in severe renal failure if possible. ## Contraindications * **Hypermagnesemia:** Elevated serum magnesium levels. * **Heart Block:** Greater than first-degree heart block (unless a pacemaker is present). * **Myocardial Infarction:** In patients with myocardial infarction, especially if hypotension is present. * **Hypocalcemia:** Magnesium sulphate can exacerbate hypocalcemia. ## Adverse Effects * **Cardiovascular:** Hypotension, flushing, electrocardiographic changes (prolonged PR, QRS, QT intervals), bradycardia, cardiac arrest. * **Neuromuscular:** Drowsiness, decreased deep tendon reflexes, muscle weakness, respiratory depression, flaccid paralysis. * **Gastrointestinal:** Nausea, vomiting. * **Other:** Warmth, sweating. ## Key Drug Interactions * **Neuromuscular Blockers:** Potentiates neuromuscular blockade; may prolong recovery. * **Calcium:** May antagonize the effects of calcium. * **Nifedipine:** Risk of profound hypotension and neuromuscular blockade. ## Monitoring * **Serum Magnesium Levels:** Essential, especially with prolonged infusions or in renal impairment. Therapeutic range is typically 4-7 mg/dL (2.0-3.5 mmol/L). * **Deep Tendon Reflexes:** Monitor for loss of reflexes, indicating toxicity. * **Respiratory Rate:** Monitor for respiratory depression. * **Blood Pressure:** Monitor for hypotension. * **Urine Output:** Adequate renal function is crucial for excretion. ## Clinical Pearls * Magnesium sulphate is the drug of choice for eclampsia prophylaxis and treatment. * IV administration should be slow to avoid hypotension and respiratory depression. * Always have calcium gluconate readily available as an antidote for magnesium toxicity. * Ensure adequate hydration and monitor urine output to prevent accumulation in renal impairment. *** *This information is intended for healthcare professionals. Always consult the most current prescribing information and institutional protocols before administering any medication.*