Magnesium sulfate


Generic Medicine Info
Indications and Dosage
Intramuscular
Eclampsia
Adult: Prevention and treatment: Initially, 10 g administered as 5 g in each buttock at onset of labour or caesarean delivery, then 5 g every 4 hours for at least 24 hours after delivery. Dosage recommendations may vary among individual products and between countries (refer to detailed product guideline).

Intramuscular
Hypomagnesaemia
Adult: Mild to moderate deficiency: 1 g (8.12 mEq or 2 mL of the 50% solution) every 6 hours for 4 doses or based on serum magnesium levels. Dosage recommendations may vary among individual products and between countries (refer to detailed product guideline).

Intravenous
Hypomagnesaemia
Adult: For asymptomatic patients: 1-2 g infused over 1-2 hours (mild deficiency); 2-4 g infused over 2-12 hours (moderate deficiency); 4-8 g infused over 4-24 hours (severe deficiency). For symptomatic patients: Initially, 1-2 g given as a bolus over 2-15 minutes; may repeat dose according to response. May administer additional 4-8 g over 12-24 hours (hemodynamically unstable patients); 1-2 g over 5-60 minutes, then 4-8 g over 12-24 hours (haemodynamically stable). Dosage recommendations may vary among individual products and between countries (refer to detailed product guideline).

Intravenous
Eclampsia
Adult: Prevention and treatment of seizures: Initially, 4-6 g over 15-30 minutes at onset of labour or caesarean delivery, then 1-2 g/hour continuous infusion for at least 24 hours after delivery. Max infusion rate: 3 g/hour. May give additional 2-4 g via bolus inj if seizure occurs. Dosage recommendations may vary among individual products and between countries (refer to detailed product guideline).

Oral
Constipation
Adult: 5-15 g in 250 mL water. May repeat dose in 4 hours. Max: 2 doses per day.
Renal Impairment
IV:
Hypomagnesaemia:
Reduce dose by 50%.

Eclampsia:
Severe: Max: 20 g during 48-hour period.
Incompatibility
Polymyxin B sulfate, Na tartrates, K tartrates, soluble phosphates and arsenates, alkali carbonates, bicarbonates and hydroxides, Ca, clindamycin, hydrocortisone Na succinate, procaine, salicylates, streptomycin sulfate, tetramycin sulfate.
Contraindications
Oral: Acute gastrointestinal conditions. IV/IM: Heart block, myocardial damage, hepatic encephalopathy, hepatic failure, renal failure.
Special Precautions
Patient with myasthenia gravis or other neuromuscular disease. Debilitated patients. Renal impairment. Elderly. Pregnancy and lactation.
Adverse Reactions
Significant: Hypermagnesaemia.
Gastrointestinal disorders: Gastrointestinal discomfort, diarrhoea.
Metabolism and nutrition disorders: Hypocalcaemia, hypophosphataemia, hypertonic dehydration.
Potentially Fatal: Magnesium toxicity leading to CV arrest and/or respiratory paralysis (parenteral).
IM/IV/Parenteral: D
MonitoringParameters
IV: Monitor vital signs, deep tendon reflexes; magnesium concentrations if frequent or prolonged dosing; renal function; ECG monitoring. Obstetrics: Monitor patient status, vital signs, oxygen saturation, respiration, deep tendon reflexes, level of consciousness, foetal heart rate, maternal uterine activity, renal function. Monitor magnesium concentrations every 4 hours in patients with renal dysfunction.
Overdosage
Symptoms: Hypermagnesaemia, bradycardia, loss of deep tendon reflexes, heart block, respiratory paralysis, cardiac arrest. Management: Restrict magnesium intake to treat mild hypermagnesaemia. In severe hypermagnesaemia, ventilatory and circulatory support may be required. Administer Ca gluconate (10-20 mL of 10% Ca gluconate) by slow IV inj to reverse the effects on CV and respiratory systems. Give adequate fluids to promote renal magnesium clearance. Haemodialysis using a magnesium-free dialysis solution may be necessary in patients with renal impairment or for whom other methods prove ineffective.
Drug Interactions
May potentiate the effects of tubocurarine. Increased risk of cardiopulmonary events with calcium channel blockers and diuretics. May cause profound hypotension with nifedipine. Reduced efficacy with calcium salts. May interfere with the absorption of ACE inhibitors (e.g. captopril, enalapril, fosinopril), antibacterials and antifungals (e.g. azithromycin, cefaclor, cefpodoxime, isoniazid, itraconazole, ketoconazole, methenamine, tetracyclines, rifampicin, quinolone antibacterials), antivirals (atazanavir, tipranavir), antihistamines (fexofenadine), bisphosphonates; corticosteroids (deflazacort), dipyridamole, antiepileptics (e.g. gabapentin, phenytoin), lansoprazole, levothyroxine, mycophenolate, rosuvastatin, antipsychotics (e.g. sulpiride, phenothiazines), chloroquine, hydroxychloroquine, penicillamine, and digoxin if given concomitantly. May reduce absorption of eltrombopag. May reduce plasma concentration of ulipristal, erlotinib.
Action
Description: Magnesium is an important cofactor for enzymatic reactions. It plays an important role in neurochemical transmission and muscular excitability. Magnesium sulfate when taken orally increases peristaltic activity by causing osmotic retention of fluids, thus resulting in bowel evacuation. When administered parenterally, it decreases levels of acetylcholine in motor nerve terminals. It also acts on the myocardium by decreasing the rate of SA node impulse formation and prolonging the conduction time.
Synonym: epsom salt.
Onset: Anticonvulsant: 1 hour (IM); Immediate (IV). Laxative: 0.5-6 hours (oral).
Duration: Anticonvulsant: 3-4 hours (IM); 30 minutes (IV).
Pharmacokinetics:
Absorption: Slowly and poorly absorbed from the gastrointestinal tract (approx one-third is absorbed from the small intestine).
Distribution: Distributed to bones and extracellular fluids. Crosses the placenta, enters breastmilk. Plasma protein-binding: 30%, to albumin.
Excretion: Via urine (as magnesium); faeces (as unabsorbed drug).
Storage
Store between 20-25°C.
ATC Classification
A06AD04 - magnesium sulfate ; Belongs to the class of osmotically acting laxatives.
B05XA05 - magnesium sulfate ; Belongs to the class of electrolyte solutions used in I.V. solutions.
References
Anon. Magnesium Sulfate. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 08/01/2021.

Anon. Magnesium Sulfate. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 08/01/2021.

Buckingham R (ed). Magnesium. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 08/01/2021.

Epsom Salt Crystal (Cardinal Health). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 08/01/2021.

Epsom Salt Granule (Equate Wal-Mart Stores, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 08/01/2021.

Epsom Salt Granule for Solution (CVS Pharmacy). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 08/01/2021.

Epsom Salts BP (L.C.M. Ltd.). MHRA. https://products.mhra.gov.uk. Accessed 08/01/2021.

Joint Formulary Committee. Magnesium Sulfate. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 08/01/2021.

Magnesium Sulfate 1g/10ml Solution for Injection (Macarthys Laboratories Ltd). MHRA. https://products.mhra.gov.uk. Accessed 08/01/2021.

Magnesium Sulfate 20% w/v Injection (Aurum Pharmaceuticals Ltd). MHRA. https://products.mhra.gov.uk. Accessed 08/01/2021.

Magnesium Sulfate for Solution (Hospira, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 08/01/2021.

Magnesium Sulfate Heptahydrate Injection, Solution (Baxter Healthcare Corporation). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 08/01/2021.

Magnesium Sulfate Heptahydrate Injection, Solution (Fresenius Kabi Norge AS). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 08/01/2021.

Magnesium Sulfate Paste BP (KL Pharmaceutical Limited). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 08/01/2021.

Disclaimer: This information is independently developed by MIMS based on Magnesium sulfate from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2021 MIMS. All rights reserved. Powered by MIMS.com
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