magnesium sulfate

magnesium /mag·ne·si·um/ (Mg) (mag-ne´ze-um) a chemical element, at. no. 12; its salts are essential in nutrition, being required for the activity of many enzymes, especially those concerned with oxidative phosphorylation. Various salts, including m. chloride, m. gluceptate, m. gluconate, and m. lactate are used as electrolyte replenishers.

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magnesium carbonate  an antacid.

magnesium chloride  an electrolyte replenisher and a pharmaceutic necessity for hemodialysis and peritoneal dialysis fluids.

magnesium citrate  a saline laxative used for bowel evacuation before diagnostic procedures or surgery of the colon.

magnesium hydroxide  an antacid and laxative.

magnesium oxide  an antacid and laxative; also used as a preventative for hypomagnesemia and as a sorbent in pharmaceutical preparations.

magnesium salicylate  see salicylate.

magnesium silicate  MgSiO3, a silicate salt of magnesium; the most common hydrated forms found in nature are asbestos and talc.

magnesium sulfate  Epsom salt; an anticonvulsant and electrolyte replenisher, also used as a laxative and local antiinflammatory.

magnesium trisilicate  a compound of magnesium oxide and silicon dioxide with varying proportions of water; an antacid.

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magnesium sulfate

n.

A colorless crystalline compound used as a cathartic and applied locally as an anti-inflammatory agent.

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magnesium sulfate,

a salt of magnesium.

indications It is prescribed parenterally to prevent seizures, especially in preeclampsia and acute nephritis in children, and orally to treat constipation and heartburn and to correct magnesium deficiency.

contraindications It is used with caution in patients with renal impairment or hypersensitivity to the drug. Respiratory depression, severe cardiac myopathy, heart block, or symptoms of appendicitis or fecal impaction prohibit its use. It is also prohibited in patients in toxemia of pregnancy during the 2 hours before labor.

adverse effects The most serious adverse effect is circulatory collapse from excessive serum concentrations of magnesium. Respiratory depression, confusion, and muscle weakness also may occur.

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magnesium (Mg) [mag-ne´ze-um]

a chemical element, atomic number 12, atomic weight 24.312. (See Appendix 6.) Its salts are essential in nutrition, being required for the activity of many enzymes, especially those concerned with oxidative phosphorylation. It is found in the intra- and extracellular fluids and is excreted in urine and feces. The normal serum level is approximately 2 mEq/L. Magnesium deficiency causes irritability of the nervous system with tetany, vasodilation, convulsions, tremors, depression, and psychotic behavior.

Homeostasis of magnesium in extracellular fluids. The normal serum magnesium level is regulated by intestinal and renal function. Most of the body's magnesium is stored in bones, muscle, and soft tissue. From Malarkey and McMorrow, 2000.

magnesium carbonate an antacid.

magnesium chloride an electrolyte replenisher and a pharmaceutic necessity for hemodialysis and peritoneal dialysis fluids.

magnesium citrate a saline laxative used for bowel evacuation before diagnostic procedures or surgery of the colon; administered orally.

magnesium hydroxide an antacid and cathartic.

magnesium oxide an antacid and a sorbent in pharmaceutical preparations; called also magnesia.

magnesium salicylate see salicylate.

magnesium silicate MgSiO₃, a silicate salt of magnesium; the most common hydrated forms found in nature are asbestos and talc.

magnesium sulfate Epsom salt; an anticonvulsant and electrolyte replenisher, also used as a laxative and local antiinflammatory.

magnesium trisilicate a combination of magnesium oxide and silicon dioxide with varying proportions of water; used as a gastric antacid.

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magnesium (Mg),

n an elemental metal with an atomic weight of 24.32. Magnesium is an essential nutritional substance. Deficiency produces irritability of the nervous system and trophic disturbances.

magnesium sulfate,

n a salt of magnesium; also called Epsom salts, used as a therapeutic bath and as a purgative.

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magnesium

a chemical element, atomic number 12, atomic weight 24.312, symbol Mg. See Table 6. Its salts are essential in nutrition, being required for the activity of many enzymes, especially those concerned with oxidative phosphorylation. It is found in the intra- and extracellular fluids and is excreted in urine and feces.

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magnesium ammonium phosphate (MAP)

a common constituent of urinary calculi. See urolithiasis.

blood magnesium

level of magnesium in the blood.

magnesium carbonate, magnesium hydroxide, magnesium oxide, magnesium phosphate, magnesium trisilicate

compounds used as antacids.

magnesium chloride

used as a source of magnesium in the treatment of hypomagnesemia in cattle, and as a chemical defibrillator in cardiopulmonary resuscitation.

magnesium citrate

a mild cathartic.

magnesium gluconate

a magnesium replenisher.

magnesium nutritional deficiency

is most important in the part that it plays in lactation tetany in ruminants. It also causes deformities of the limbs and nervous signs of tremor and convulsions in pigs. See also lactation tetany (1).

magnesium salicylate

the magnesium salt of salicylic acid used as an antiarthritic.

magnesium silicate

talcum powder; capable of causing starch granulomatous peritonitis if introduced into the peritoneal cavity, so it has been superseded by other compounds for use on surgeon's gloves.

magnesium sulfate

Epsom salts; used as an electrolyte replenisher, cathartic and local anti-inflammatory.

magnesium sulfate-chloral hydrate mixture

see chloral hydrate and magnesium sulfate.

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magnesium sulfate Warning - High-alert drug!

Epsom Salts

Pharmacologic class: Mineral

Therapeutic class: Electrolyte replacement, laxative, antacid, anticonvulsant

Pregnancy risk category A (magnesium sulfate), NR (magnesium citrate, hydroxide, oxide), unknown (magnesium chloride, gluconate)

Action

Increases osmotic gradient in small intestine, which draws water into intestines and causes distention. These effects stimulate peristalsis and bowel evacuation. In antacid action, reacts with hydrochloric acid in stomach to form water and increase gastric pH. In anticonvulsant action, depresses CNS and blocks transmission of peripheral neuromuscular impulses.

Availability

magnesium chloride

Injection: 20%

magnesium citrate

Oral solution: 240-ml, 296-ml, and 300-ml bottles

magnesium gluconate

Liquid: 1,000 mg/5 ml

Tablets: 500 mg

magnesium hydroxide

Liquid: 400 mg/5 ml

Liquid concentrate: 800 mg/5 ml

Tablets (chewable): 300 mg

magnesium oxide

Capsules: 140 mg

Tablets: 400 mg, 420 mg, 500 mg

magnesium sulfate

Granules (for oral use): 120 g, 4 lb

Injection: 10%, 12.5%, 25%, 50%

⊘Indications and dosages

➣ Mild magnesium deficiency

Adults: 1 g (2 ml of 50% sulfate solution) I.M. q 6 hours for four doses

➣ Severe hypomagnesemia

Adults: 250 mg (2 mEq)/kg (sulfate) I.M. within 4-hour period, or 5 g (approximately 40 mEq) in 1 liter 5% dextrose injection or 0.9% sodium chloride solution by I.V. infusion over 3 hours

➣ Hypomagnesemia treatment

Adults and children: Dosage individualized based on severity of deficiency; may give citrate, gluconate, hydroxide, oxide, or sulfate.

➣ Hypomagnesemia prophylaxis

Adults and children: Dosage based on normal recommended daily magnesium intake; may give citrate, gluconate, hydroxide, oxide, or sulfate.

➣ Supplemental magnesium in total parenteral nutrition (TPN)

Adults: 8 to 24 mEq/day (sulfate) by I.V. infusion, added to TPN solution

➣ Constipation

Adults and children ages 12 and older: 15 g (sulfate granules) in 240 ml water; or 30 to 60 ml/day P.O. (hydroxide) given with water; or a single dose of 10 to 30 ml P.O. (hydroxide concentrate); or one bottle of oral solution (citrate), as directed

Children ages 6 to 11: 5 to 10 g (sulfate granules) in 120 ml water; or a single dose of 2.5 to 5 ml P.O. (sulfate) in a half-glass of water; or 15 to 30 ml P.O. daily (hydroxide) given with water; or a single dose of 7.5 to 15 ml P.O. (hydroxide concentrate); or three to four tablets (hydroxide); or 50 to 100 ml, as directed, of oral solution (citrate)

Children ages 2 to 5: Single dose of 5 to 15 ml P.O. (hydroxide); or 2.5 to 7.5 ml P.O. daily (hydroxide concentrate); or one to two tablets (hydroxide); or 4 to 12 ml oral solution (citrate), as directed

➣ Indigestion

Adults and children ages 12 and older: 5 to 15 ml P.O. (hydroxide liquid) up to q.i.d. with water; or 2.5 to 7.5 ml P.O. (hydroxide liquid concentrate) up to q.i.d. with water; or 622 to 1,244 mg P.O. (hydroxide tablets) up to q.i.d.; or 400 to 800 mg P.O. (oxide tablets) daily

➣ To prevent and control seizures in preeclampsia or eclampsia

Adults: 4 to 5 g 50% sulfate solution I.M. q 4 hours, as necessary; or 4 g 10% to 20% sulfate solution I.V., not to exceed 1.5 ml/minute of 10% solution; or 4 to 5 g I.V. infusion in 250 ml of 5% dextrose or sodium chloride solution, not to exceed 3 ml/minute

➣ Acute nephritis to control hypertension, encephalopathy, and seizures in children

Children: 100 mg/kg 50% sulfate solution I.M. q 4 to 6 hours as needed; or 20 to 40 mg/kg 20% solution I.M., repeated as necessary

Off-label uses

• Bronchodilation in some asthmatic patients
• Post?myocardial infarction hypomagnesemia

Contraindications

• Hypermagnesemia
• Heart block
• Myocardial damage
• Active labor or within 2 hours of delivery

Precautions

Use cautiously in:
• renal insufficiency, abdominal pain, nausea and vomiting, rectal bleeding, anuria, hypocalcemia
• pregnant patients.

Administration

☞ Be aware that magnesium sulfate injection is a high-alert drug.
• Know that I.V. use is reserved for life-threatening seizures.
• When giving magnesium sulfate I.V., don't exceed concentration of 20% or infusion rate of 150 mg/minute, except in seizures caused by severe eclampsia. Too-rapid I.V. infusion may cause hypotension and asystole.
• When giving magnesium sulfate I.M. to adults, use concentration of 25% to 50%; when giving to infants and children, don't exceed 20%.

Route	Onset	Peak	Duration
P.O.	3-6 hr	4 hr	Unknown
I.V.	Immediate	Unknown	30 min
I.M.	60 min	Unknown	3-4 hr

Adverse reactions

CNS ( with I.V. use): confusion, decreased reflexes, dizziness, syncope, sedation, hypothermia, paralysis

CV (with I.V. use): hypotension, arrhythmias, circulatory collapse

GI: nausea, vomiting, cramps, flatulence, anorexia

Metabolic: hypermagnesemia, hypocalcemia

Musculoskeletal (with I.V. use): muscle weakness, flaccidity

Respiratory: respiratory paralysis

Skin: diaphoresis

Other: allergic reaction, injection site reaction, laxative dependence (with repeated or prolonged use)

Interactions

Drug-drug. Aminoquinolones, nitrofurantoin, penicillamine, tetracyclines: decreased absorption of these drugs (with oral magnesium)

CNS depressants: additive effects

Digoxin: heart block, conduction changes (with I.V. use)

Enteric-coated drugs: faster dissolution of these drugs

Neuromuscular blockers: increased effects of these drugs (with I.V. use)

Drug-diagnostic tests. Calcium, magnesium: increased levels (with I.V. use)

Patient monitoring

☞ When giving prolonged or repeated I.V. infusions, assess patellar reflex and monitor for respiratory rate of 16 breaths/minute or more.
☞ With I.V. use, monitor blood magnesium level (desired level is 3 to 6 mg/dl or 2.5 to 5 mEq/L). Check for signs and symptoms of magnesium toxicity (hypotension, nausea, vomiting, ECG changes, muscle weakness, mental or respiratory depression, coma). Keep injectable calcium on hand to counteract magnesium toxicity.
• Monitor urine output, which should measure 100 ml or more every 4 hours.
☞ If I.V. magnesium was given before delivery, assess neonate for signs and symptoms of magnesium toxicity, such as neuromuscular or respiratory depression.
• Monitor electrolyte levels and liver function tests.

Patient teaching

☞ Teach patient about adverse reactions. Instruct him to report symptoms that occur during I.V. administration.
• Advise patient to consult prescriber before using magnesium if he's taking other drugs. Magnesium may delay or enhance absorption of other drugs.
• Inform patient that repeated or prolonged use of magnesium citrate, hydroxide, or sulfate may cause laxative dependence. Inform him that healthy diet and exercise can reduce need for laxatives.
• Tell pregnant female to make sure prescriber knows she's pregnant before taking drug.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.

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magnesium sulfate

Cardiology An agent which, administered IV, may slow the ventricular response to rapid AF, and act in tandem with pharmacotherapy to ↓ the heart rate attributed to intracellular magnesium depletion seen in ethanol abuse, renal failure, in hypokalemia, hyponatremia, or in Pts receiving digoxin or diuretics. See Atrial fibrillation.