Mag-Ox, Maox, Par-Mag, Uro-Mag
Classifications: antacid; saline cathartic; Therapeutic: antacid; magnesium supplement; laxative
Prototype: Magnesium hydroxide
Pregnancy Category: A
400 mg, 420 mg, 500 mg tablets; 140 mg capsules
Nonsystemic antacid with high neutralizing capacity and relatively long duration of action.
Acts as an antacid in low doses and a mild saline laxative at higher doses. Also effective as a magnesium supplement.
Essentially the same as magnesium hydroxide. May also be used as magnesium supplement.
Abdominal pain, nausea, vomiting, diarrhea, severe kidney dysfunction, fecal impaction, intestinal obstruction or perforation,
ileus; rectal bleeding, colostomy, ileostomy; AV block; hypermagnesia; children <2 y.
Cardiac disease, renal disease, renal impairment; electrolyte imbalance; pregnancy (category A), lactation.
Route & Dosage
Adult: PO 2801500 mg with water or milk q.i.d., p.c. and h.s.
Adult: PO 24 g with water or milk h.s.
Adult: PO 4001200 mg/d in divided doses
- Separate administration of this drug from other oral drugs by 12 h.
- Store at 15°30° C (59°86° F) in airtight containers. On exposure to air, magnesium oxide
rapidly absorbs moisture and carbon dioxide.
Adverse Effects (≥1%)GI: Diarrhea,
abdominal cramps, nausea; hypermagnesemia, kidney stones
See magnesium hydroxide
3050% from GI tract. Elimination:
Assessment & Drug Effects
- Monitor for dehydration, hypokalemia, and hyponatremia (see Appendix F) since drug may cause intense bowel evacuation.
- Lab tests: Check patients on prolonged therapy periodically for electrolyte imbalance (i.e., hypermagnesemia).
Patient & Family Education
- Liquid preparation is reportedly more effective than the tablet form, as with other antacids.