Indication

Heartburn, Constipation, Indigestion, Gastrointestinal hyperacidity, Osmotic laxative

Adult Dose

Constipation\r\nMagnesium hydroxide (400 mg/5 mL): 30-60 mL/day PO at bedtime or in divided doses\r\n\r\nAcid Indigestion\r\nMagnesium hydroxide (400 mg/5 mL): 5-15 mL PO q4hr; no more than 4 doses per 24-hour period

Child Dose

Constipation\r\n<2 years: Safety and efficacy not established\r\n\r\nSuspension\r\n2-6 years: 5-15 mL/day of regular-strength liquid PO at bedtime or in divided doses\r\n6-12 years: 15-30 mL/day (400 mg/5 mL)\r\n>12 years: 30-60 mL/day (400 mg/5 mL) \r\n\r\nAcid Indigestion\r\nLiquid\r\n<12 years: Not recommended\r\n>12 years: 5-15 mL (400 mg/5 mL) PO q4hr; no more than 4 doses per 24-hour period

Contraindication

Intestinal obstruction, faecal impaction; renal failure; appendicitis.

Mode of Action

Magnesium hydroxide increases peristaltic activity causing osmotic retention of fluids, thus resulting in bowel evacuation. It also reduces stomach acid by reacting with hydrochloric acid to form Mg chloride.

Precaution

Colostomy, ileostomy; electrolyte imbalance. Monitor for toxicity in patients with impaired renal function. Pregnancy.\r\n\r\nLactation: Use in nursing mothers appears to be safe

Side Effect

Abdominal cramping, Diarrhea, Electrolyte imbalance, Hypotension, Muscle weakness, Respiratory depression, Hypermagnesaemia (in patients with renal impairment). Paralytic ileus.

Interaction

Decreases absorption of tetracyclines and biphosphonates. Separate administration of these and other drugs by around 2 hr.