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Quick facts
- How it is given
- intravenous
- Type
- human prescription drug
- RxNorm ID
- 829757
We do not publish dosing. How much of this medicine to take, how often, and for how long depends on your age, weight, kidney and liver function, other conditions and other medicines. That is a decision for the person who prescribes or dispenses it. Follow the directions on your own pack and ask your pharmacist if anything is unclear.
What it is used to treat
Magnesium Sulfate in 5% Dextrose Injection is indicated for: • Prevention of eclampsia in patients with preeclampsia • Treatment of seizures and prevention of recurrent seizures in patients with eclampsia Magnesium Sulfate in 5% Dextrose Injection is indicated for ( 1 ): • Prevention of eclampsia in patients with preeclampsia ( 1 ) • Treatment of seizures and prevention of recurrent seizures in patients with eclampsia ( 1 )
About this medicine
Magnesium Sulfate in 5% Dextrose Injection, USP is a sterile, nonpyrogenic solution of magnesium sulfate heptahydrate and dextrose in water for injection for intravenous use. Each 100 mL contains 1 gram of magnesium sulfate heptahydrate and dextrose, hydrous 5 grams in water for injection [see How Supplied/Storage and Handling (16) ] . Magnesium Sulfate in 5% Dextrose Injection, USP may contain sulfuric acid and/or sodium hydroxide for pH adjustment. The pH is 4.5 (3.5 to 6.5). Magnesium Sulfate, USP heptahydrate is chemically known as sulfuric acid magnesium salt (1:1), heptahydrate and chemically designated MgSO 4 ∙ 7H 2 O, with a molecular weight of 246.47. It occurs as colorless crystals or white powder freely soluble in water. Dextrose, USP is chemically designated D-glucose, monohydrate, a hexose sugar freely soluble in water. The molecular formula is C 6 H 12 O 6 ∙ H 2 O and the molecular weight is 198.17. It has the following structural formula: Water for Injection, USP is chemically designated H 2 O. Water can permeate from inside the flexible plastic container into the overwrap [see Dosage and Administration (2.1) ] but not in amounts sufficient to affect the solution significantly. Solutions in contact with the plastic container may leach out certain chemical components from the plastic in very small amounts; however, biological testing was supportive of the safety of the plastic container materials. Exposure to temperatures above 25°C (77°F) during transport and storage will lead to minor losses in moisture content. Higher temperatures lead to greater losses. It is unlikely that these minor losses will lead to clinically significant changes within the expiration period. Chemical Structure
How it works
12.1 Mechanism of Action Magnesium prevents seizures in patients with preeclampsia and controls seizures in patients with eclampsia by blocking neuromuscular transmission and decreasing the amount of acetylcholine liberated at the end plate by the motor nerve impulse. Magnesium has a depressant effect on the central nervous system [see Drug Interactions (7) ] . Magnesium acts peripherally to produce vasodilation.
Who should not take it
Magnesium Sulfate in 5% Dextrose Injection is contraindicated in patients: • with heart block or myocardial damage • in diabetic coma • with myasthenia gravis [see Warnings and Precautions (5.6) ] • Heart block or myocardial damage ( 4 ) • Diabetic coma ( 4 ) • Myasthenia gravis ( 4 , 5.6 )
Warnings and cautions
• Fetal-neonatal toxicity with prolonged use : Administration beyond 5 to 7 days is not recommended and can lead to hypocalcemia and bone abnormalities ( 2.2 , 5.1 ) • Risk of magnesium toxicity : Monitor magnesium concentrations and clinical signs of magnesium toxicity including respiratory depression, an injectable calcium salt should be immediately available to counteract hazards, for significant toxicity stop Magnesium Sulfate in 5% Dextrose Injection ( 5.2 ) • Risk of elevated blood glucose: Solutions containing dextrose should be used with caution in patients with known prediabetes or diabetes mellitus ( 5.3 ) • Co-administration with unapproved tocolytics : Do not use concomitantly with beta adrenergic agents such as terbutaline and calcium channel blockers such as nifedipine ( 5.4 ) • Aluminum toxicity : Aluminum may reach toxic concentrations with prolonged parenteral administration in patients with renal impairment ( 5.5 ) • Exacerbation of Myasthenia Gravis : Use is contraindicated because use in patients with underlying myasthenia gravis can precipitate a myasthenic crisis ( 5.6 ) 5.1 Fetal-Neonatal Toxicity with Prolonged Use Continuous administration of magnesium sulfate beyond 5 to 7 days in pregnant women can lead to hypocalcemia and bone abnormalities in the developing fetus, including skeletal demineralization and osteopenia. In addition, cases of neonatal fracture have been reported. Neonates of women receiving Magnesium Sulfate in 5% Dextrose Injection (especially with prolonged maternal use) are at risk for magnesium toxicity including hyporeflexia, hypotonia, and respiratory depression. There is one reported case of neonatal death as the result of magnesium toxicity after transplacental exposure. The shortest duration of magnesium sulfate treatment that can lead to fetal harm is not known. Administration of Magnesium Sulfate in 5% Dextrose Injection beyond 5 to 7 days is not recommended. 5.2 Risk of Magnesium Toxicity Patients receiving Magnesium Sulfate in 5% Dextrose Injection are at risk for magnesium toxicity including respiratory depression, acute renal failure and rarely, pulmonary edema. […]
Reported side effects
The following adverse reactions have been identified in clinical studies or postmarketing reports. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Cardiovascular: hypotension, circulatory collapse, cardiac depression including bradycardia Central Nervous System: central nervous system depression leading to respiratory paralysis, visual disturbances, flushing, sweating, hypothermia Metabolic: hypocalcemia with signs of tetany, hypermagnesemia Neurologic: lethargy, sedation, somnolence, myasthenic crisis Neuromuscular: depressed deep tendon reflexes, flaccid paralysis Pulmonary: decreased respiratory rate, pulmonary edema The most common adverse reactions are flushing, sweating, hypotension, depressed reflexes, flaccid paralysis, hypothermia, circulatory collapse, cardiac and central nervous system (CNS) depression proceeding to respiratory paralysis and hypocalcemia. Bradycardia, pulmonary edema, decreased respiratory rate, lethargy, sedation, somnolence, visual disturbances, and hypermagnesemia are also reported ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Pfizer Inc., at 1-800-438-1985 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch .
Interactions with other medicines
Table 1 presents the potential clinical impact of medications that may be commonly administered concomitantly with Magnesium Sulfate in 5% Dextrose Injection in the clinical setting. Table 1: Potential Clinically Significant Drug Interactions with Magnesium Sulfate in 5% Dextrose Injection For drug incompatibility information [see Dosage and Administration (2.4) ] . Neuromuscular Blocking Agents Clinical Impact: • Potentiation and prolongation of neuromuscular blockade is possible with the concomitant use of magnesium sulfate and neuromuscular blocking agents [see Clinical Pharmacology (12.2) ] . • The underlying mechanism of this interaction may involve suppression of peripheral neuromuscular function by decreasing acetylcholine release, reduction of endplate sensitivity, and decreased muscle fiber excitability with magnesium sulfate therapy. Intervention: • Monitor respiration and the depth of neuromuscular blockade frequently (e.g., train-of-four monitoring) when a neuromuscular blocking agent is used concomitantly with Magnesium Sulfate in 5% Dextrose Injection. • Adjust the dosage of the neuromuscular blocking agent accordingly to maintain the desired level of musculoskeletal activity. The amount of reversal agent(s) required to achieve adequate reversal of the neuromuscular blocking agent(s) may also be increased. Examples: • Depolarizing neuromuscular blockers: succinylcholine • Non-depolarizing neuromuscular blockers: atracurium, cisatracurium, pancuronium, rocuronium, vecuronium Narcotics and/or Propofol Clinical Impact: • Potentiation and prolongation of analgesia and CNS depression is possible with the concomitant use of Magnesium Sulfate in 5% Dextrose Injection with narcotics and/or propofol. The potential for magnesium sulfate to affect other CNS depressants is unknown [see Clinical Pharmacology (12.2) ] . • The underlying mechanism of this interaction may involve antagonism of N-methyl-D-aspartate (NMDA) by magnesium sulfate therapy. Intervention: • Monitor the depth of CNS depression frequently using a reliable instrument. • Adjust the narcotic and/or propofol dosage accordingly to maintain the desired level of analgesia and sedation. […]
Use in specific groups
Patients with severe renal impairment and/or a urine output less than 100 mL every 4 hours are at greater risk for increased magnesium concentrations that may lead to toxicity ( 8.6 ) 8.1 Pregnancy Risk Summary Magnesium Sulfate in 5% Dextrose Injection is indicated in pregnant women for the prevention of eclampsia in women with preeclampsia and the treatment of seizures and prevention of recurrent seizures in women with eclampsia. Fetal, neonatal, and maternal risks are discussed throughout the labeling. Clinical Considerations Labor or Delivery: Magnesium Sulfate in 5% Dextrose Injection is not approved for the treatment of pre-term labor. Administration of Magnesium Sulfate in 5% Dextrose Injection to pregnant women longer than 5 to 7 days may lead to hypocalcemia and bone abnormalities in the developing fetus, including skeletal demineralization and osteopenia [see Warnings and Precautions (5.1) ] . 8.2 Lactation The use of intravenous magnesium in pregnant women increases human milk magnesium concentrations only slightly and oral absorption of magnesium by the infant is poor. The effect of intravenous magnesium on milk production is unknown. The developmental and health benefits to the neonate of breastfeeding should be considered along with the mother's clinical need for Magnesium Sulfate in 5% Dextrose Injection and any potential adverse effects on the breastfed infant from Magnesium Sulfate in 5% Dextrose Injection or from the underlying maternal condition. 8.4 Pediatric Use The safety and effectiveness of Magnesium Sulfate in 5% Dextrose Injection have been established for the prevention of eclampsia in adolescents with preeclampsia and the treatment of seizures and prevention of recurrent seizures in adolescents with eclampsia. Dosing recommendation in pregnant adolescent patients are the same as for pregnant adult patients [see Dosage and Administration (2.2) ] . 8.6 Renal Impairment Magnesium is excreted solely by the kidneys. […]
If too much is taken
Manifestations of magnesium toxicity include a drop in blood pressure, difficulty breathing, and disappearance of the patellar reflex. As serum magnesium rises above 4 mEq per liter, the deep tendon reflexes decrease. As the serum magnesium level approaches 10 mEq per liter, the tendon reflexes disappear and respiratory paralysis may occur [see Warnings and Precautions (5.2) ] . Other signs and symptoms of magnesium overdosage include flushing, sweating, hypotension, weakness, hypothermia, circulatory collapse, cardiac and central nervous system depression proceeding to respiratory paralysis, cardiac arrest, and prolongation of PR and QRS intervals. Patients with renal impairment and underlying neuromuscular diseases such as myasthenia gravis may experience magnesium intoxication at lower magnesium concentrations (Magnesium Sulfate in 5% Dextrose Injection is contraindicated in patients with myasthenia gravis). If patient is experiencing magnesium toxicity, immediately discontinue Magnesium Sulfate in 5% Dextrose Injection. Artificial respiration may be required. Administer an injectable calcium salt to counteract the potential hazards of magnesium toxicity [see Warnings and Precautions (5.2) ] . Hypermagnesemia in the newborn (after administration of Magnesium Sulfate in 5% Dextrose Injection to the mother) may require resuscitation and assisted ventilation via endotracheal intubation or intermittent positive pressure ventilation as well as intravenous calcium.
Storing it safely
Storage Store at 20°C to 25°C (68°F to 77°F). [See USP Controlled Room Temperature.] Protect from freezing.
Before you take anything new
Tell your pharmacist or doctor about every medicine you take — including ones bought without a prescription, herbal products and supplements. Interactions are one of the most common avoidable causes of harm from medicines, and a pharmacist can check your full list in a couple of minutes.
This page is built from the openFDA record of the U.S. Food and Drug Administration's approved labelling for this product, effective 23 April 2026. Label text has been shortened and reformatted for readability; safety wording has not been altered in meaning. FDA labelling describes products approved in the United States — brand names, strengths, formulations and approved uses may differ in your country. Always read the leaflet that comes with your own pack. PocketsInfo is not affiliated with, and is not endorsed by, the FDA. Retrieved 2026-07-30.