magnesium sulfate (Rx)

Brand and Other Names:MgSO4
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

injectable solution

  • 40mg/mL
  • 80mg/mL
  • 50%

infusion solution

  • 1g/100mL
  • 2g/100mL

Hypomagnesemia

Mild: 1 g IM q6hr for 4 doses

Severe

  • Asymptomatic: 4-8 g at ≤1 g/hr
  • Symptomatic: 4-8 g at ≤4 g over 4-5 min

Toxemia of Pregnancy

Indicated to prevent seizures associated with pre-eclampsia, and for control of seizures with eclampsia

4-5 g (diluted in 250 mL NS/D5W) IV in combination with either (a) up to 10 g (20 mL of undiluted 50% solution) divided and administered IM into each buttock or (b) after initial IV dose, 1-2 g/hr IV; may administer q4hr as necessary

Torsades de Pointes

With pulse (ACLS): 1-2 g slow IV (diluted in 50-100 mL D5W) over 5-60 minutes, then 0.5-1 g/hr IV

Cardiac arrest (ACLS): 1-2 g slow IV (diluted in 10 mL D5W) over 5-20 minutes

Preterm Labor (Off-label)

Used as a tocolytic to stop preterm labor

Loading dose: 4-6 g IV over 20 minutes; maintenance: 2-4 g/hr IV for 12-24 hours as tolerated after contractions cease

Do not exceed 5-7 days of continuous treatment; longer treatment duration may lead to hypocalcemia in developing fetus resulting in neonates with skeletal abnormalities related to osteopenia

Dosing Modifications

Severe renal impairment: Do not exceed 20 g/48 hr

Dosage Forms & Strengths

injectable solution

  • 40mg/mL
  • 80mg/mL
  • 50%

infusion solution

  • 1g/100mL
  • 2g/100mL

Acute Nephritis

100 mg/kg IM q4-6hr PRN or 20-40 mg/kg IM PRN  

Severe: 100-200 mg/kg IV as 1-3% solution; administer total dose within 1 hr, one-half within first 15-20 minutes

Hypomagnesemia

IV/IM: 25-50 mg/kg q4-6hr for 3-4 doses PRN  

PO: 100-200 mg/kg q6hr

Bronchospasm (Off-label)

25-50 mg/kg IV over 10-20 minutes

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Interactions

Interaction Checker

and magnesium sulfate

No Results

     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

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             activity indicator 

            Contraindicated (0)

              Serious - Use Alternative (7)

              • baloxavir marboxil

                magnesium sulfate will decrease the level or effect of baloxavir marboxil by cation binding in GI tract. Avoid or Use Alternate Drug. Baloxavir may bind to polyvalent cations resulting in decreased absorption. Studies in monkeys showed concurrent use with calcium, aluminum, or iron caused significantly decreased plasma levels. Human studies not conducted.

              • demeclocycline

                magnesium sulfate decreases levels of demeclocycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

              • doxycycline

                magnesium sulfate decreases levels of doxycycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

              • eltrombopag

                magnesium sulfate decreases levels of eltrombopag by inhibition of GI absorption. Applies only to oral form of both agents. Contraindicated. Separate by at least 4 hours.

              • minocycline

                magnesium sulfate decreases levels of minocycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

              • oxytetracycline

                magnesium sulfate decreases levels of oxytetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

              • tetracycline

                magnesium sulfate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

              Monitor Closely (21)

              • atracurium

                magnesium sulfate increases effects of atracurium by pharmacodynamic synergism. Use Caution/Monitor. Interaction occurs with parenteral magnesium.

              • ciprofloxacin

                magnesium sulfate decreases levels of ciprofloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Coadministration of ciprofloxacin with multivalent cation-containing products may reduce the bioavailability of ciprofloxacin by 90%. Administer ciprofloxacin at least 2 hours before or 6 hours after using these products. Use alternatives if available.

              • cisatracurium

                magnesium sulfate increases effects of cisatracurium by pharmacodynamic synergism. Use Caution/Monitor. Interaction occurs with parenteral magnesium.

              • delafloxacin

                magnesium sulfate will decrease the level or effect of delafloxacin by cation binding in GI tract. Modify Therapy/Monitor Closely. Oral delafloxacin form chelates with alkaline earth and transition metal cations. Administer oral delafloxacin at least 2 hr before or 6 hr after these agents.

              • dichlorphenamide

                dichlorphenamide and magnesium sulfate both decrease serum potassium. Use Caution/Monitor.

              • fleroxacin

                magnesium sulfate decreases levels of fleroxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

              • gemifloxacin

                magnesium sulfate decreases levels of gemifloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

              • levofloxacin

                magnesium sulfate decreases levels of levofloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

              • moxifloxacin

                magnesium sulfate decreases levels of moxifloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

              • nifedipine

                magnesium sulfate, nifedipine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Hypotension, neuromuscular blockade.

              • ofloxacin

                magnesium sulfate decreases levels of ofloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

              • onabotulinumtoxinA

                magnesium sulfate increases effects of onabotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Interaction occurs with parenteral magnesium.

              • pancuronium

                magnesium sulfate increases effects of pancuronium by pharmacodynamic synergism. Use Caution/Monitor. Interaction occurs with parenteral magnesium.

              • penicillamine

                magnesium sulfate decreases levels of penicillamine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

              • rapacuronium

                magnesium sulfate increases effects of rapacuronium by pharmacodynamic synergism. Use Caution/Monitor. Interaction occurs with parenteral magnesium.

              • rilpivirine

                magnesium sulfate decreases levels of rilpivirine by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Coadministration of antacids with rilpivirine may cause significant decreases in rilpivirine plasma concentrations because of increased gastric pH. If antacids must be administered, they should given at least 2 hr before or at least 4 hr after rilpivirine.

              • rimabotulinumtoxinB

                magnesium sulfate, rimabotulinumtoxinB. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Anticholinergics may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.

              • rocuronium

                magnesium sulfate increases effects of rocuronium by pharmacodynamic synergism. Use Caution/Monitor. Interaction occurs with parenteral magnesium.

              • sodium polystyrene sulfonate

                sodium polystyrene sulfonate increases levels of magnesium sulfate by decreasing renal clearance. Use Caution/Monitor. Risk of seizure.

              • succinylcholine

                magnesium sulfate increases effects of succinylcholine by pharmacodynamic synergism. Use Caution/Monitor. Interaction occurs with parenteral magnesium.

              • vecuronium

                magnesium sulfate increases effects of vecuronium by pharmacodynamic synergism. Use Caution/Monitor. Interaction occurs with parenteral magnesium.

              Minor (40)

              • amikacin

                amikacin decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • amiloride

                amiloride increases levels of magnesium sulfate by decreasing renal clearance. Minor/Significance Unknown.

              • amphotericin B deoxycholate

                amphotericin B deoxycholate decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • bazedoxifene/conjugated estrogens

                bazedoxifene/conjugated estrogens decreases levels of magnesium sulfate by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.

              • bendroflumethiazide

                bendroflumethiazide decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • bumetanide

                bumetanide decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • calcitonin salmon

                calcitonin salmon increases levels of magnesium sulfate by decreasing renal clearance. Minor/Significance Unknown.

              • chlorothiazide

                chlorothiazide decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • chlorthalidone

                chlorthalidone decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • conjugated estrogens

                conjugated estrogens decreases levels of magnesium sulfate by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.

              • conjugated estrogens, vaginal

                conjugated estrogens, vaginal decreases levels of magnesium sulfate by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.

              • cyclopenthiazide

                cyclopenthiazide decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • dextrose

                dextrose decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • dextrose (Antidote)

                dextrose (Antidote) decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • digoxin

                digoxin decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • doxercalciferol

                doxercalciferol increases levels of magnesium sulfate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

              • drospirenone

                drospirenone increases levels of magnesium sulfate by decreasing renal clearance. Minor/Significance Unknown.

              • estradiol

                estradiol decreases levels of magnesium sulfate by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.

              • estrogens conjugated synthetic

                estrogens conjugated synthetic decreases levels of magnesium sulfate by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.

              • estrogens esterified

                estrogens esterified decreases levels of magnesium sulfate by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.

              • estropipate

                estropipate decreases levels of magnesium sulfate by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.

              • ethacrynic acid

                ethacrynic acid decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • furosemide

                furosemide decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • gentamicin

                gentamicin decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • glucagon intranasal

                glucagon intranasal increases levels of magnesium sulfate by decreasing renal clearance. Minor/Significance Unknown.

              • hydrochlorothiazide

                hydrochlorothiazide decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • ibandronate

                magnesium sulfate decreases levels of ibandronate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

              • indapamide

                indapamide decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • mannitol

                mannitol decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • mestranol

                mestranol decreases levels of magnesium sulfate by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.

              • methyclothiazide

                methyclothiazide decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • metolazone

                metolazone decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • neomycin PO

                neomycin PO decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • nitrofurantoin

                magnesium sulfate decreases levels of nitrofurantoin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

              • paromomycin

                paromomycin decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • spironolactone

                spironolactone increases levels of magnesium sulfate by decreasing renal clearance. Minor/Significance Unknown.

              • streptomycin

                streptomycin decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • tobramycin

                tobramycin decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • torsemide

                torsemide decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

              • triamterene

                triamterene increases levels of magnesium sulfate by decreasing renal clearance. Minor/Significance Unknown.

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              Adverse Effects

              Frequency Not Defined

              Circulatory collapse

              Respiratory paralysis

              Hypothermia

              Pulmonary edema

              Depressed reflexes

              Hypotension

              Flushing

              Drowsiness

              Depressed cardiac function

              Diaphoresis

              Hypocalcemia

              Hypophosphatemia

              Hyperkalemia

              Visual changes

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              Warnings

              Contraindications

              Hypersensitivity

              Myocardial damage, diabetic coma, heart block

              Hypermagnesemia

              Hypercalcemia

              Administration during 2 hours preceding delivery for mothers with toxemia of pregnancy

              Cautions

              Fetal skeletal demineralization, hypocalcemia, and hypermagnesemia abnormalities reported with continuous long-term use (ie, longer than 5-7 days) for off-label treatment of preterm labor in pregnant women; the effect on the developing fetus may result in neonates with skeletal abnormalities

              In patients with renal impairment, ensure that renal excretory capacity is not exceeded

              Use with caution in digitalized patients

              Use with extreme caution in patients with myasthenia gravis or other neuromuscular disease

              Hypomagnesemia is usually associated with hypokalemia (potassium levels must be normalized)

              Monitor renal function, blood pressure, respiratory rate, and deep tendon reflex when magnesium sulfate is administered parenterally

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              Pregnancy & Lactation

              Pregnancy category: D

              Fetal skeletal demineralization, hypocalcemia, and hypermagnesemia reported with continuous long-term use (ie, longer than 5-7 days) for off-label treatment of preterm labor in pregnant women; the effect on the developing fetus may result in neonates with skeletal abnormalities

              Continuous administration of magnesium sulfate injection to treat preterm labor is not approved and that the safety and efficacy of use for this indication are not established

              Lactation: Safe

              Pregnancy Categories

              A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

              B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

              C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

              D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

              X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

              NA: Information not available.

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              Pharmacology

              Mechanism of Action

              Depresses CNS, blocks peripheral neuromuscular transmission, produces anticonvulsant effects; decreases amount of acetylcholine released at end-plate by motor nerve impulse

              Slows rate of SA node impulse formation in myocardium and prolongs conduction time

              Promotes movement of calcium, potassium, and sodium in and out of cells and stabilizes excitable membranes

              Promotes osmotic retention of fluid in colon, causing distention and increased peristaltic activity, which subsequently results in bowel evacuation

              Absorption

              Onset (anticonvulsant): IV, immediate; IM, 1 hr

              Duration (anticonvulsant): IV, 30 min; IM, 3-4 hr

              Distribution

              Protein bound: 30%

              Extracellular distribution: 1-2%

              Elimination

              Excretion: Urine

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              Administration

              IV Incompatibilities

              Solution: IV fat emulsion 10%

              Additive: Amphotericin B, cyclosporine, dobutamine, polymyxin B sulfate, procaine, sodium bicarbonate

              Y-site: Alatrofloxacin, amiodarone (at 500 mg/mL MgSO4; may be compatible at 20 mg/mL), amphotericin B cholesteryl sulfate, cefepime, ciprofloxacin (?)

              IV Preparation

              Intermittent infusion: Dilute to 60 mg/mL

              IV Administration

              Infuse over 2-4 hr (hypomagnesemia) or as otherwise specified; rate not to exceed 125 mg/kg/hr

              In severe cases, half of the dose may be infused over first 15-20 minutes

              Rapid infusions (over 10-20 minutes) may be used for treatment of severe asthma or torsades de pointes ventricular tachycardia

              Cautiously infuse diluted solution through patent IV line

              IM Administration

              Dilute to maximum concentration of 200 mg/mL before injection

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              Images

              BRAND FORM. UNIT PRICE PILL IMAGE
              magnesium sulfate injection
              -
              4 mEq/mL (50 %) vial
              magnesium sulfate injection
              -
              4 mEq/mL (50 %) vial
              magnesium sulfate injection
              -
              4 mEq/mL (50 %) vial
              magnesium sulfate injection
              -
              4 mEq/mL (50 %) vial
              magnesium sulfate injection
              -
              4 mEq/mL (50 %) vial
              magnesium sulfate injection
              -
              4 mEq/mL (50 %) vial
              magnesium sulfate injection
              -
              4 mEq/mL solution

              Copyright © 2010 First DataBank, Inc.

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              Patient Handout

              Select a drug:
              Patient Education
              magnesium sulfate injection

              NO MONOGRAPH AVAILABLE AT THIS TIME

              USES: Consult your pharmacist.

              HOW TO USE: Consult your pharmacist.

              SIDE EFFECTS: Consult your pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

              PRECAUTIONS: Consult your pharmacist.

              DRUG INTERACTIONS: Consult your pharmacist.Keep a list of all your medications with you, and share the list with your doctor and pharmacist.

              OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

              NOTES: No monograph available at this time.

              MISSED DOSE: Consult your pharmacist.

              STORAGE: Consult your pharmacist.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.

              Information last revised July 2016. Copyright(c) 2021 First Databank, Inc.

              IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

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              Formulary

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              The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

              Tier Description
              1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
              2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
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              5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
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              Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.