Magnesium Sulfate

Magnesium sulfate (magnesium sulfate (magnesium sulfate injection) injection) is indicated in the following conditions:

Convulsions (treatment) - Intravenous magnesium sulfate (magnesium sulfate (magnesium sulfate injection) injection) is indicated for immediate control of life-threatening convulsions in the treatment of severe toxemias (pre-eclampsia and eclampsia) of pregnancy and in the treatment of acute nephritis in children.

Hypomagnesemia (prophylaxis and treatment) - Magnesium sulfate (magnesium sulfate (magnesium sulfate injection) injection) is indicated for replacement therapy in magnesium deficiency, especially in acute hypomagnesemia accompanied by signs of tetany similar to those of hypocalcemia.

Magnesium sulfate (magnesium sulfate (magnesium sulfate injection) injection) is also used to prevent or treat magnesium deficiency in patients receiving total parenteral nutrition.

Tetany, uterine (treatment) - Magnesium sulfate (magnesium sulfate (magnesium sulfate injection) injection) is indicated in uterine tetany as a myometrial relaxant.

Magnesium sulfate (magnesium sulfate (magnesium sulfate injection) injection) should be given very cautiously in the presence of serious impairment of renal function since it is excreted almost entirely by the kidneys.

The principle hazard in parenteral magnesium therapy is the production of abnormally high levels of magnesium in the plasma. Such high levels may cause flushing, sweating, hypotension, circulatory collapse and depression of cardiac and central nervous system function. The most immediate danger to life is respiratory depression.

During the period of parenteral therapy with magnesium salts, the patient should be watched carefully. A preparation of calcium, such as the gluconate or gluceptate should be at hand for intravenous administration as an antidote.

In the presence of severe renal insufficiency, no more than 20 grams of magnesium should be given within a forty-eight hour period. In eclampsia, however, renal function is not seriously impaired and magnesium may be more rapidly excreted.

This product contains aluminum that may be toxic. Aluminum may reach toxic levels with prolonged parenteral administration if kidney function is impaired. Premature neonates are particularly at risk because their kidneys are immature, and they require large amounts of calcium and phosphate solutions, which contain aluminum.

Research indicates that patients with impaired kidney function, including premature neonates, who receive parenteral levels of aluminum at greater than 4 to 5 mcg/kg/day accumulate aluminum at levels associated with central nervous system and bone toxicity. Tissue loading may occur at even lower rates of administration.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Magnesium Sulfate falls into category D:

It has been shown that use of Magnesium Sulfate in pregnant women caused some babies to be born with problems. However, in some serious situations, the benefit of using this medication may be greater than the risk of harm to the baby.

Take magnesium sulfate exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The Magnesium Sulfate dose your doctor recommends will be based on the following (use any or all that apply):

• the condition being treated
• other medical conditions you have
• other medications you are taking
• how you respond to this medication
• your weight
• your height
• your age
• your gender

Magnesium Sulfate is available in the following doses:

• Magnesium Sulfate 1 G/50 Ml-d5% Intravenous Solution
• Magnesium Sulfate 10 G Added To D5% 250 Ml Intravenous Solution
• Magnesium Sulfate 10 G/1000 Ml Intravenous Solution
• Magnesium Sulfate 10 G/500 Ml Intravenous Solution
• Magnesium Sulfate 10 Mg/ml-d5% Intravenous Solution
• Magnesium Sulfate 100 Mg/ml Injectable Solution
• Magnesium Sulfate 1000 Mg/ 50 Ml-nacl 0.9% Intravenous Solution
• Magnesium Sulfate 120 Mg/ml-d5% Intravenous Solution
• Magnesium Sulfate 125 Mg/ml Injectable Solution
• Magnesium Sulfate 2 G Added To D5% 50 Ml Intravenous Solution
• Magnesium Sulfate 2 G/100 Ml-d5% Intravenous Solution
• Magnesium Sulfate 2 G/100 Ml-nacl 0.9% Intravenous Solution
• Magnesium Sulfate 2 G/50 Ml-d5% Intravenous Solution
• Magnesium Sulfate 2 G/50 Ml-nacl 0.9% Intravenous Solution
• Magnesium Sulfate 20 G Added To Lr 500 Ml Intravenous Solution
• Magnesium Sulfate 20 Mg/ml-d5% Intravenous Solution
• Magnesium Sulfate 3 G Added To D5% 100 Ml Intravenous Solution
• Magnesium Sulfate 30 Mg/ml-d5% Intravenous Solution
• Magnesium Sulfate 4 G Added To D5% 100 Ml Intravenous Solution
• Magnesium Sulfate 40 Mg/ml Injectable Solution
• Magnesium Sulfate 40 Mg/ml-d5% Intravenous Solution
• Magnesium Sulfate 40 Mg/ml-lr Intravenous Solution
• Magnesium Sulfate 50 G Added To Lr 500 Ml Intravenous Solution
• Magnesium Sulfate 50% Injectable Solution
• Magnesium Sulfate 6 G Added To Nacl 0.9% 100 Ml Intravenous Solution
• Magnesium Sulfate 6 G/100 Ml-d5% Intravenous Solution
• Magnesium Sulfate 80 Mg/ml Injectable Solution
• Magnesium Sulfate 80 Mg/ml-d5% Intravenous Solution
• Magnesium Sulfate 80 Mg/ml-lr Injectable Solution
• Magnesium Sulfate 83 Mg/ml-d5% Intravenous Solution
• Magnesium Sulfate 83 Mg/ml-lr Intravenous Solution
• Magnesium Sulfate Compounding Powder
• Magnesium/potassium/sodium Sulfates 1.6 G-3.13 G-17.5 G/177 Ml Oral Liquid
• Multivitamin With Minerals Vitamin B Complex With C And Minerals Oral Capsule
• Physiological Irrigating Solution Tis-u-sol Irrigation Solution

Do not use magnesium sulfate as a laxative without medical advice if you have:

• severe stomach pain;

• nausea or vomiting;

• a perforated bowel;

• a bowel obstruction or severe constipation;

• colitis or toxic megacolon; or

• a sudden change in bowel habits lasting 2 weeks or longer.

Ask a doctor or pharmacist if it is safe for you to take this medicine if you have:

• diabetes;

• kidney disease;

• an eating disorder (anorexia or bulimia);

• if you have already been using a laxative for longer than 1 week; or

• if you on a low-magnesium diet.

It is not known whether magnesium sulfate will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medication.

It is not known whether magnesium sulfate passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

Use exactly as directed on the label, or as prescribed by your doctor.

Never use a higher dose of magnesium sulfate than recommended on the package label, or as your doctor has directed. Using too much magnesium sulfate can cause serious, life-threatening side effects.

Magnesium sulfate may be used orally (by mouth) or as a soak. Follow your doctor's instructions or the directions on the package.

To take magnesium sulfate orally, dissolve one dose in 8 ounces of water. Stir this mixture and drink all of it right away. You may add a small amount of lemon juice to improve the taste of this mixture.

Magnesium sulfate taken orally should produce a bowel movement within 30 minutes to 6 hours.

Drink plenty of liquids while you are taking magnesium sulfate.

If you have rectal bleeding or if you do not have a bowel movement after using magnesium sulfate as a laxative, stop using the medication and call your doctor at once. These may be signs of a more serious condition.

To use magnesium sulfate as an epsom salt soak, dissolve in a large amount of water in a large bowl, a bucket, a foot tub, or a bath tub. Follow the directions on the product label about how much epsom salt to use per gallon of water.

Store at room temperature away from moisture and heat.

Since magnesium sulfate is used on an as needed basis, you are not likely to miss a dose.

Prevention and Control of Seizures

Used parenterally for prevention and control of seizures in toxemias (preeclampsia or eclampsia) of pregnancy and in various other conditions.58 67 91 95 (See Preeclampsia and Eclampsia and also see Other Seizure Etiologies under Uses.)

Preeclampsia and Eclampsia

Generally considered anticonvulsant drug of choice for prevention and control of seizures in severe preeclampsia or in eclampsia;58 59 60 61 104 appears to be more effective than phenytoin in preeclampsia, and more effective than phenytoin and diazepam in eclampsia.58 60 61 101 102 104

The American College of Obstetricians and Gynecologists (ACOG) strongly recommends intrapartum/postpartum use of magnesium sulfate in women with severe preeclampsia to prevent eclampsia.58

Routine use not recommended in women with preeclampsia without severe features (e.g., systolic BP ≥160 mm Hg or diastolic BP ≥110 mm Hg, thrombocytopenia, impaired liver or renal function, pulmonary edema, new-onset cerebral or visual disturbances).58 Individualize decision to initiate therapy in these patients based on the presence of certain warning signs of seizures (e.g., headache, altered mental state, blurred vision, scotomata, clonus, right upper quadrant pain).58

Clinical course of preeclampsia may change rapidly and unexpectedly; monitor patients closely and initiate therapy if progression to severe preeclampsia occurs.58

ACOG strongly recommends administration of parenteral magnesium sulfate in patients with eclampsia; continue therapy for ≥24 hours after last seizure.58

Other Seizure Etiologies

May be used parenterally to control seizures associated with epilepsy, glomerulonephritis, or hypothyroidism, since low plasma concentrations of magnesium may be a contributing cause of seizures in these conditions.67

Has been used for immediate control of life-threatening seizures in children with acute nephritis.95

Prevention and Treatment of Hypomagnesemia

Used to correct or prevent hypomagnesemia in patients receiving total parenteral nutrition.67

Also used in the treatment of acute hypomagnesemia accompanied by signs of tetany similar to those of hypocalcemia; usually, serum magnesium concentrations are below the lower limits of normal (1.5–2.5 or 3 mEq/L), and serum calcium concentrations are either normal (4.3–5.3 mEq/L) or elevated in such cases.67

Preterm Labor and Fetal Neuroprotection

Has been used to inhibit uterine contractions in preterm labor (tocolysis)† and prolong gestation when considered beneficial.14 69 However, efficacy and safety not established and not labeled by FDA for this use.67 69 75

ACOG and other experts support the short-term (≤48 hours) obstetric use of magnesium sulfate for appropriate conditions and durations of therapy.91 This includes short-term (i.e., ≤48 hours) prolongation of pregnancy to allow time for administration of antenatal corticosteroids; corticosteroid administration prior to anticipated preterm birth is strongly associated with decreased neonatal morbidity and mortality.69 71 72 73 91 92

Also may be used for fetal neuroprotection prior to preterm delivery to reduce the risk of cerebral palsy†.28 29 69 89 91

May be contraindicated by maternal or fetal conditions.67 69 (See Contraindications under Cautions.)

Do not use for >5–7 days for tocolysis; such prolonged use in pregnant women has been associated with adverse fetal effects (e.g., hypocalcemia, osteopenia, bone demineralization, fractures).67 75 77 78 79 80 81 82 83 84 85 86 91 (See Fetal/Neonatal Morbidity and Mortality under Cautions.)

ACOG states that maintenance treatment with tocolytic drugs is not recommended because it is not effective in preventing preterm birth and improving neonatal outcomes.69

Limited data indicate that combination therapy with another tocolytic agent may be more effective than single-agent therapy, but may increase risk of maternal morbidity; use with caution.19 24 25 27 69

Concurrent use of magnesium sulfate and nifedipine may be particularly risky and potentially harmful.32 69 (See Specific Drugs under Interactions.)

Arrhythmias

Used IV successfully for the treatment of life-threatening arrhythmias such as atypical VT† (torsades de pointes).8 9 10 94 400 401

Considered one of several preferred drugs in the treatment of polymorphic VT suspected of being torsades de pointes† in patients in whom initial attempts at correcting or managing potential precipitating factors (e.g., ischemic cardiac events, electrolyte imbalance, drugs known to prolong the QT interval) have not been successful.64 94 401

Should not be used routinely during cardiac arrest, but may be considered when arrest rhythm is associated with torsades de pointes.400 401 402 403

Has been used IV in the management of paroxysmal atrial tachycardia when other measures have failed and there is no evidence of myocardial damage.67

Acute MI

Has been administered IV adjunctively to reduce cardiovascular morbidity and mortality (e.g., through reduction in ventricular arrhythmias and/or limitation of infarct size and reperfusion injury) associated with acute MI†;2 6 7 34 35 36 37 38 39 64 however, evidence of benefit is contradictory.34 44 45 46 47 64 106

Should not be used routinely in patients with acute MI, but may be reasonable in patients with documented magnesium deficiency or torsades de pointes.105 106

Acute Asthma

Has been used in the treatment of acute asthma†.96 98 99 100 196

There is some evidence that the drug may improve pulmonary function (i.e., peak expiratory flow rate and forced expiratory volume in 1 second) and reduce hospitalizations, particularly in patients with severe exacerbations.98 99 196

Although current evidence does not support routine use in all patients with acute asthma, may be beneficial, and thus may be considered, in patients with severe acute asthma.98 99 100 196

Barium Poisoning

Has been administered IV to counteract the intense muscle stimulating effects of barium poisoning.67

Specific Drugs

General

Administer with caution if flushing and sweating occurs. When barbiturates, narcotics or other hypnotics (or systemic anesthetics) are to be given in conjunction with magnesium, their dosage should be adjusted with caution because of additive CNS depressant effects of magnesium.

Because magnesium is removed from the body solely by the kidneys, the drug should be used with caution in patients with renal impairment. Urine output should be maintained at a level of 100 mL or more during the four hours preceding each dose. Monitoring serum magnesium levels and the patient’s clinical status is essential to avoid the consequences of overdosage in toxemia. Clinical indications of a safe dosage regimen include the presence of the patellar reflex (knee jerk) and absence of respiratory depression (approximately 16 breaths or more/minute). When repeated doses of the drug are given parenterally, knee jerk reflexes should be tested before each dose and if they are absent, no additional magnesium should be given until they return. Serum magnesium levels usually sufficient to control convulsions range from 3 to 6 mg/100 mL (2.5 to 5 mEq/liter). The strength of the deep tendon reflexes begins to diminish when magnesium levels exceed 4 mEq/liter. Reflexes may be absent at 10 mEq magnesium/liter, where respiratory paralysis is a potential hazard. An injectable calcium salt should be immediately available to counteract the potential hazards of magnesium intoxication in eclampsia.

50% Magnesium Sulfate Injection, USP must be diluted to a concentration of 20% or less prior to intravenous infusion. Rate of administration should be slow and cautious, to avoid producing hypermagnesemia. The 50% solution also should be diluted to 20% or less for intramuscular injection in infants and children.

Laboratory Tests

Magnesium Sulfate injection should not be given unless hypomagnesemia has been confirmed and the serum concentration of magnesium is monitored. The normal serum level is 1.5 to 2.5 mEq/L.

Drug Interactions

CNS Depressants  When barbiturates, narcotics or other hypnotics (or systemic anesthetics), or other CNS depressants are to be given in conjunction with magnesium, their dosage should be adjusted with caution because of additive CNS depressant effects of magnesium. CNS depression and peripheral transmission defects produced by magnesium may be antagonized by calcium.

Neuromuscular Blocking Agents  Excessive neuromuscular block has occurred in patients receiving parenteral Magnesium Sulfate and a neuromuscular blocking agent; these drugs should be administered concomitantly with caution.

Cardiac Glycosides  Magnesium Sulfate should be administered with extreme caution in digitalized patients, because serious changes in cardiac conduction which can result in heart block may occur if administration of calcium is required to treat magnesium toxicity.

Pregnancy

Teratogenic Effects

Pregnancy Category D (See WARNINGSand PRECAUTIONS)

See WARNINGSand PRECAUTIONS. 

Magnesium Sulfate can cause fetal abnormalities when administered beyond 5 to 7 days to pregnant women. There are retrospective epidemiological studies and case reports documenting fetal abnormalities such as hypocalcemia, skeletal demineralization, osteopenia and other skeletal abnormalities with continuous maternal administration of Magnesium Sulfate for more than 5 to 7 days.1-10 Magnesium Sulfate injection should be used during pregnancy only if clearly needed. If this drug is used during pregnancy, the woman should be apprised of the potential harm to the fetus.

Nonteratogenic Effects

When administered by continuous intravenous infusion (especially for more than 24 hours preceding delivery) to control convulsions in a toxemic woman, the newborn may show signs of magnesium toxicity, including neuromuscular or respiratory depression (See OVERDOSAGE).

Labor and Delivery

Continuous administration of Magnesium Sulfate is an unapproved treatment for preterm labor. The safety and efficacy of such use have not been established. The administration of Magnesium Sulfate outside of its approved indication in pregnant women should be by trained obstetrical personnel in a hospital setting with appropriate obstetrical care facilities.

Nursing Mothers

Since magnesium is distributed into milk during parenteral Magnesium Sulfate administration, the drug should be used with caution in nursing women.

Geriatrics

Geriatric patients often require reduced dosage because of impaired renal function. In patients with severe impairment, dosage should not exceed 20 grams in 48 hours. Serum magnesium should be monitored in such patients.

The adverse effects of parenterally administered magnesium usually are the result of magnesium intoxication. These include flushing, sweating, hypotension, depressed reflexes, flaccid paralysis, hypothermia, circulatory collapse, cardiac and central nervous system depression proceeding to respiratory paralysis. Hypocalcemia with signs of tetany secondary to Magnesium Sulfate therapy for eclampsia has been reported.

Anticonvulsant activity: IM: 3-4 hours; IV: 30 minutes

Protein Binding

30%, to albumin

Dose represented as magnesium sulfate unless stated otherwise. Note: Serum magnesium is poor reflection of repletional status as the majority of magnesium is intracellular; serum concentrations may be transiently normal for a few hours after a dose is given, therefore, aim for consistently high normal serum concentrations in patients with normal renal function for most efficient repletion.

Note: 1 g of magnesium sulfate = 98.6 mg elemental magnesium = 8.12 mEq elemental magnesium = magnesium 4.06 mmol

Constipation (occasional): Oral:

Children 6 to <12 years: 1 to 2 level teaspoons of granules dissolved in water; may repeat in 4 to 6 hours (maximum: 2 doses/24 hours)

Children ≥12 years and Adolescents: Refer to adult dosing.

Hypomagnesemia, treatment: Note: Treatment depends on severity and clinical status: IV, I.O.: 25 to 50 mg/kg/dose over 10 to 20 minutes (over several minutes for torsade de pointes); maximum single dose: 2000 mg (PALS, 2010)

Hypomagnesemia, prevention (parenteral nutrition supplementation) (ASPEN [Mirtallo, 2004]): IV:

≤50 kg: 0.3 to 0.5 mEq elemental magnesium/kg/day

>50 kg: 10 to 30 mEq elemental magnesium daily

Asthma (acute severe exacerbations) (off-label use): IV: Children and Adolescents: 25 to 75 mg/kg (maximum: 2000 mg) as a single dose over 20 to 60 minutes (GINA 2015; NAEPP, 2007); recommended as adjunctive therapy for severe life-threatening exacerbations and for exacerbations that remain severe after 1 hour of intensive conventional therapy (NAEPP, 2007)

RDA (IOM, 1997): Children

1 to 3 years: 80 mg elemental magnesium daily

4 to 8 years: 130 mg elemental magnesium daily

9 to 13 years: 240 mg elemental magnesium daily

14 to 18 years:

Females: 360 mg elemental magnesium daily

Pregnant females: 400 mg elemental magnesium daily

Breast-feeding females: 360 mg elemental magnesium daily

Males: 410 mg elemental magnesium daily

Refer to indication-specific dosing for obesity-related information (may not be available for all indications).

IV: Dilute to ≤20% in a compatible solution (eg, D5W, NS) for IV infusion.

IM: A 25% or 50% concentration may be used for adults and dilution to a ≤20% solution is recommended for children.

Oral: Dissolve granules in 8 ounces of water prior to administration. May add lemon juice to improve taste.

Topical: Dissolve 2 cups of granules per gallon of warm water to use as a soaking aid.

Whole grains, legumes and dark-green leafy vegetables are dietary sources of magnesium (IOM, 1997).

Alfacalcidol: May increase the serum concentration of Magnesium Salts. Consider therapy modification

Alpha-Lipoic Acid: Magnesium Salts may decrease the absorption of Alpha-Lipoic Acid. Alpha-Lipoic Acid may decrease the absorption of Magnesium Salts. Consider therapy modification

Bisphosphonate Derivatives: Magnesium Salts may decrease the serum concentration of Bisphosphonate Derivatives. Management: Avoid administration of oral magnesium salts within: 2 hours before or after tiludronate/clodronate/etidronate; 60 minutes after oral ibandronate; or 30 minutes after alendronate/risedronate. Exceptions: Pamidronate; Zoledronic Acid. Consider therapy modification

Calcitriol (Systemic): May increase the serum concentration of Magnesium Salts. Management: Consider using a non-magnesium-containing antacid or phosphate-binding product in patients also receiving calcitriol. If magnesium-containing products must be used with calcitriol, serum magnesium concentrations should be monitored closely. Consider therapy modification

Calcium Channel Blockers: May enhance the adverse/toxic effect of Magnesium Salts. Magnesium Salts may enhance the hypotensive effect of Calcium Channel Blockers. Monitor therapy

Calcium Polystyrene Sulfonate: Laxatives (Magnesium Containing) may enhance the adverse/toxic effect of Calcium Polystyrene Sulfonate. More specifically, concomitant use of calcium polystyrene sulfonate with magnesium-containing laxatives may result in metabolic alkalosis or with sorbitol may result in intestinal necrosis. Management: Avoid concomitant use of calcium polystyrene sulfonate (rectal or oral) and magnesium-containing laxatives. Avoid combination

CNS Depressants: Magnesium Sulfate may enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Deferiprone: Magnesium Salts may decrease the serum concentration of Deferiprone. Management: Separate administration of deferiprone and oral medications or supplements that contain polyvalent cations by at least 4 hours. Consider therapy modification

Dolutegravir: Magnesium Salts may decrease the serum concentration of Dolutegravir. Management: Administer dolutegravir at least 2 hours before or 6 hours after oral magnesium salts. Consider therapy modification

Doxercalciferol: May enhance the hypermagnesemic effect of Magnesium Salts. Management: Consider using a non-magnesium-containing antacid or phosphate-binding product in patients also receiving doxercalciferol. If magnesium-containing products must be used with doxercalciferol, serum magnesium concentrations should be monitored closely. Consider therapy modification

Eltrombopag: Magnesium Salts may decrease the serum concentration of Eltrombopag. Management: Administer eltrombopag at least 2 hours before or 4 hours after oral administration of any magnesium-containing product. Consider therapy modification

Gabapentin: Magnesium Salts may enhance the CNS depressant effect of Gabapentin. Specifically, high dose intravenous/epidural magnesium sulfate may enhance the CNS depressant effects of gabapentin. Magnesium Salts may decrease the serum concentration of Gabapentin. Management: Administer gabapentin at least 2 hours after oral magnesium salts administration. Monitor patients closely for evidence of reduced response to gabapentin therapy. Monitor for CNS depression if high dose IV/epidural magnesium sulfate is used. Consider therapy modification

Levothyroxine: Magnesium Salts may decrease the serum concentration of Levothyroxine. Management: Separate administration of oral levothyroxine and oral magnesium salts by at least 4 hours. Consider therapy modification

Multivitamins/Fluoride (with ADE): Magnesium Salts may decrease the serum concentration of Multivitamins/Fluoride (with ADE). Specifically, magnesium salts may decrease fluoride absorption. Management: To avoid this potential interaction separate the administration of magnesium salts from administration of a fluoride-containing product by at least 1 hour. Consider therapy modification

Mycophenolate: Magnesium Salts may decrease the serum concentration of Mycophenolate. Management: Separate doses of mycophenolate and oral magnesium salts. Monitor for reduced effects of mycophenolate if taken concomitant with oral magnesium salts. Consider therapy modification

Neuromuscular-Blocking Agents: Magnesium Salts may enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy

Phosphate Supplements: Magnesium Salts may decrease the serum concentration of Phosphate Supplements. Management: This applies only to oral phosphate and magnesium administration. Administer oral phosphate supplements at least 1 hour before, or 2 hours after, oral magnesium salt administration. Exceptions: Sodium Glycerophosphate Pentahydrate. Consider therapy modification

Quinolone Antibiotics: Magnesium Salts may decrease the serum concentration of Quinolone Antibiotics. Management: Administer oral quinolones several hours before (4 h for moxi- and sparfloxacin, 2 h for others) or after (8 h for moxi-, 6 h for cipro/dela-, 4 h for lome-, 3 h for gemi-, and 2 h for levo-, nor-, or ofloxacin or nalidixic acid) oral magnesium salts. Exceptions: LevoFLOXacin (Oral Inhalation). Consider therapy modification

Raltegravir: Magnesium Salts may decrease the serum concentration of Raltegravir. Management: Avoid the use of oral / enteral magnesium salts with raltegravir. No dose separation schedule has been established that adequately reduces the magnitude of interaction. Avoid combination

Sodium Polystyrene Sulfonate: Laxatives (Magnesium Containing) may enhance the adverse/toxic effect of Sodium Polystyrene Sulfonate. More specifically, concomitant use of sodium polystyrene sulfonate with magnesium-containing laxatives may result in metabolic alkalosis or with sorbitol may result in intestinal necrosis. Management: Avoid concomitant use of sodium polystyrene sulfonate (rectal or oral) and magnesium-containing laxatives. Avoid combination

Tetracycline Derivatives: Magnesium Salts may decrease the absorption of Tetracycline Derivatives. Only applicable to oral preparations of each agent. Consider therapy modification

Trientine: May decrease the serum concentration of Magnesium Salts. Magnesium Salts may decrease the serum concentration of Trientine. Consider therapy modification

Magnesium crosses the placenta; serum concentrations in the fetus are similar to those in the mother (Idama 1998; Osada 2002). Continuous maternal use for >5 to 7 days (in doses such as those used for preterm labor, an off-label use) may cause fetal hypocalcemia and bone abnormalities, as well as fractures in the neonate. Magnesium sulfate injection is used for the prevention and treatment of seizures in pregnant or postpartum women with severe pre-eclampsia or eclampsia (ACOG 2013; ACOG 652 2016). Magnesium sulfate may also be used prior to early preterm delivery for neuroprotection to reduce the risk of cerebral palsy (ACOG 455 2010; ACOG 652 2016; Reeves 2011); specific regimens are not available, but treatment may be of benefit when birth is anticipated before 32 weeks gestation (ACOG 171 2016; ACOG 172 2016; ACOG 652 2016). Tocolytics may be used for the short-term (48 hour) prolongation of pregnancy to allow for the administration of antenatal steroids and should not be used prior to fetal viability or when the risks of use to the fetus or mother are greater than the risk of preterm birth; maintenance therapy with tocolytics is ineffective and not recommended. Magnesium sulfate can be used up to 48 hours in women at risk of delivery within 7 days; however, it is not the preferred tocolytic (ACOG 171 2016; ACOG 652 2016). Magnesium sulfate injection may be used in conjunction with other tocolytics for neuroprotection; however, an increased risk of maternal complications may be observed when used in combination with some tocolytic agents (ACOG 171 2016). Magnesium toxicity should be suspected in pregnant women receiving magnesium in respiratory and/or cardiac arrest. Medications used for the treatment of cardiac arrest in pregnancy are the same as in the non-pregnant woman. Doses and indications should follow current Advanced Cardiovascular Life Support guidelines. Appropriate medications should not be withheld due to concerns of fetal teratogenicity (Jeejeebhoy [AHA] 2015).