• As a:
  • Laxative,
  • Bowel evacuant in preparation for surgical/radiographic procedures.

Contraindicated in:

• Hypermagnesemia
• Hypocalcemia
• Anuria
• Heart block
• Active labor or within 2 hr of delivery (unless used for preterm labor).

Use Cautiously in:

• Any degree of renal insufficiency.

Derm: flushing, sweating.

GI: diarrhea.

Drug-Drug:

• Potentiates neuromuscular blocking agents.
• May decrease absorption of fluoroquinolones, nitrofurantoin, and tetracyclines and penicillamine.

Magnesium Citrate

(generic available)

• Oral solution: 240-; 296-; and 300-mL bottles (77 mEq magnesium/100 mL)^OTC;

Magnesium Hydroxide

(generic available)

• Liquid: 400 mg/5 mL (164 mg magnesium/5 mL)^OTC;
• Concentrated liquid: 800 mg/5 mL (328 mg magnesium/5 mL)^OTC;
• Chewable tablets: 300 mg (130 mg magnesium)^OTC; 600 mg (260 mg magnesium)^OTC;

• PO (Adults): Magnesium citrate: 240 mL; magnesium hydroxide (Milk of Magnesia): 30–60 mL single or divided dose or 10–20 mL as concentrate.
• PO (Children 6–12 yr): Magnesium citrate: 100 mL; magnesium hydroxide (Milk of Magnesia): 15–30 mL single or divided dose.
• PO (Children 2–5 yr): magnesium hydroxide (Milk of Magnesia): 5–15 mL single or divided dose.

magnesium citrate: Citrate of Magnesia, Citroma

magnesium hydroxide: Dulcolax Magnesia Tablets, Phillips Magnesia Tablets, Phillips Milk of Magnesia, MOM

• Essential for the activity of many enzymes.
• Play an important role in neurotransmission and muscular excitability.
• Are osmotically active in GI tract, drawing water into the lumen and causing peristalsis.

• Replacement in deficiency states.
• Evacuation of the colon.

Therapeutic Classification: laxatives

Absorption: Up to 30% may be absorbed orally.

Distribution: Widely distributed. Cross the placenta and are present in breast milk.

Metabolism/Excretion: Excreted primarily by the kidneys.

Half-life: Unknown.

magnesium citrate: Citromag

( laxative effect)

• Advise patient not to take this medication within 2 hr of taking other medications, especially fluoroquinolones, nitrofurantoin, and tetracyclines.
• Advise patient that laxatives should be used only for short-term therapy. Long-term therapy may cause electrolyte imbalance and dependence.
  • Encourage patient to use other forms of bowel regulation, such as increasing bulk in the diet, fluid intake, and mobility. Normal bowel habits are individualized; frequency of bowel movement may vary from 3 times/day to 3 times/wk.
  • Advise patient to notify health care professional if unrelieved constipation, rectal bleeding, or symptoms of electrolyte imbalance (muscle cramps or pain, weakness, dizziness) occur.

magnesium citrate: mag-NEE-zhum SI -trate

magnesium hydroxide: mag-NEE-zhum hye-DROX-ide