Dangerous Drug: Magnesium Sulfate (Epsom Salt)(mag nee’ zee um)
PREGNANCY CATEGORY A
PREGNANCY CATEGORY B
(LAXATIVE)
Drug Classes
Antiepileptic
Electrolyte
Laxative
Therapeutic Actions
Cofactor of many enzyme systems involved in neurochemical transmission and muscular excitability; prevents or controls seizures by blocking neuromuscular transmission; attracts and retains water in the intestinal lumen and distends the bowel to promote mass movement and relieve constipation.
Indications
Acute nephritis (children), to control hypertension
IV: Hypomagnesemia, replacement therapy
IV or IM: Pre-eclampsia or eclampsia
PO: Short-term treatment of constipation
PO: Evacuation of the colon for rectal and bowel examinations
To correct or prevent hypomagnesemia in patients on parenteral nutrition
Unlabeled uses: Inhibition of premature labor (parenteral), adjunct treatment of exacerbations of acute asthma; treatment torsades de pointes, atypical ventricular arrhythmias caused by hypomagnesemia
Contraindications and Cautions
Contraindicated with allergy to magnesium products; heart block, myocardial damage; abdominal pain, nausea, vomiting, or other symptoms of appendicitis; acute surgical abdomen, fecal impaction, intestinal and biliary tract obstruction, hepatitis. Do not give during 2 hr preceding delivery because of risk of magnesium toxicity in the neonate. Do not use for more than 5–7 days to stop preterm labor; not approved for this use.
Use cautiously with renal insufficiency.
Available Forms
Granules—40 mEq/5 g; injection—0.081, 0.162, 0.325, 0.65, 1, 4 mEq/mL
Dosages
Adults
Parenteral nutrition: 8–24 mEq/day IV.
Mild magnesium deficiency: 1 g IM or IV every 6 hr for 4 doses (32.5 mEq/24 hr).
Severe hypomagnesemia: Up to 246 mg/kg IM within 4 hr or 5 g (40 mEq)/1,000 mL D5W or 0.9% normal saline IV infused over 3 hr.
Eclampsia, severe pre-eclampsia: Total initial dose of 10–14 g. May infuse 4–5 g in 250 mL 5% dextrose injection or 0.9% sodium chloride IV while giving IM doses up to 10 g (5 g or 10 mL of undiluted 50% solution in each buttock). Or, may give initial IV dose of 4 g by diluting 50% solution to 10% or 20%; may inject diluted fluid (40 mL of 10% or 20 mL of 20% solution) IV over 3–4 min. Then inject 4–5 g (8 to 10 mL of 50% solution) IM into alternate buttocks every 4 hr as needed depending on patellar reflex and respiratory function. Or, after initial IV dose, may give 1–2 g/hr by constant IV infusion. Continue until paroxysms stop. To control seizures, optimal serum magnesium level is 6 mg/100 mL. Do not exceed 30–40 g in 24 hr.
IM
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