Magnesium%252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252520sulphate

## Magnesium Sulphate ### Overview Magnesium sulphate is an essential mineral that plays a crucial role in numerous biochemical functions. It is available in intravenous (IV) and intramuscular (IM) formulations. ### Primary Indications * Treatment of hypomagnesemia. * Management of eclampsia and pre-eclampsia. * Treatment of torsades de pointes. * Adjunct therapy in severe asthma exacerbations. ### Adult Dosing * **Hypomagnesemia:** * Severe: 4 to 6 grams IV infused over 10 to 60 minutes, followed by a continuous infusion of 1 to 2 grams per hour. Adjust based on serum magnesium levels. * Less severe: 1 to 2 grams IM divided into 4 doses every 4 hours, or 1 to 2 grams IV infused over 5 to 60 minutes. * **Eclampsia/Pre-eclampsia (loading dose):** 4 to 6 grams IV infused over 5 to 10 minutes. * **Eclampsia/Pre-eclampsia (maintenance dose):** 1 to 2 grams per hour IV infusion. Local protocols vary significantly. * **Torsades de Pointes:** 1 to 2 grams IV infused over 5 to 10 minutes. May repeat as needed. * **Severe Asthma:** 1.2 to 2 grams IV infused over 15 to 30 minutes. ### Pediatric Dosing * **Hypomagnesemia:** Dosing varies widely based on age and severity. A common guideline for neonates is 25-50 mg/kg/dose IV every 12-24 hours. For older children, doses of 25-50 mg/kg/dose IV (maximum 2 grams) every 4-6 hours may be used. Actual dosing depends on local protocols and serum magnesium levels. * **Eclampsia/Pre-eclampsia:** Not typically used in pediatric patients for this indication. * **Torsades de Pointes:** 25-50 mg/kg/dose IV (maximum 2 grams) infused over 10-20 minutes. * **Severe Asthma:** 25-40 mg/kg/dose IV infused over 15-30 minutes. ### Dose Adjustments No specific dose adjustment is required for renal impairment, but caution is advised. Magnesium is cleared by the kidneys, and accumulation can occur in severe renal dysfunction, potentially leading to toxicity. Use with extreme caution or avoid in patients with anuria. Dose adjustments are not typically required for hepatic impairment. ### Contraindications * Hypermagnesemia. * Heart block. * Myocardial infarction. * Severe renal impairment (anuria). * Hypersensitivity to magnesium sulphate. ### Adverse Effects * **Common:** Flushing, sweating, nausea, vomiting, decreased deep tendon reflexes, hypotension, drowsiness. * **Serious:** Respiratory depression, cardiac arrhythmias, cardiac arrest, neuromuscular blockade, hypermagnesemia (especially in renal impairment). ### Key Drug Interactions * **Neuromuscular Blocking Agents (e.g., succinylcholine, vecuronium):** Magnesium sulphate can potentiate neuromuscular blockade, increasing the risk of prolonged paralysis and respiratory depression. * **Calcium Salts:** Concurrent administration can antagonize the effects of magnesium. * **Nifedipine:** Increased risk of hypotension. * **Tetracyclines and Quinolones:** Magnesium can decrease the absorption of these antibiotics by forming insoluble complexes. Separate administration by at least 2 hours. ### Monitoring * **Serum Magnesium Levels:** Monitor frequently, especially during continuous infusions or in patients with renal impairment. Therapeutic range for hypomagnesemia is generally 1.7-2.2 mmol/L (4-5.5 mg/dL), but goals may vary. Toxicity can occur at levels > 4.0 mmol/L (10 mg/dL). * **Renal Function:** Monitor BUN and creatinine, especially in patients with suspected or known renal impairment. * **Vital Signs:** Blood pressure, heart rate, and respiratory rate. * **Deep Tendon Reflexes:** Assess for loss of reflexes, an early sign of toxicity. * **Urine Output:** Monitor for adequate output, especially in patients with renal impairment. ### Clinical Pearls * Rapid IV infusion can cause hypotension and cardiac arrhythmias. Infuse as recommended. * Monitor for signs and symptoms of hypermagnesemia, particularly in patients with reduced renal function. * Always confirm IV compatibility before co-administration with other medications. * For intramuscular administration, the injection site may be painful. Dilution may be necessary in some cases, but consult specific product information. *** *This information is intended for healthcare professionals and does not replace the need to consult the official prescribing information and current clinical guidelines. Always verify the most up-to-date drug information before making clinical decisions.*