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magnesium hydroxide

A02AA04

Forms & Strengths

Oral Suspension: 400 mg/5 mL, 1200 mg/5 mL
Chewable Tablets: 300 mg, 311 mg, 600 mg

Adult Dosing

Antacid: 400 mg to 1200 mg oral suspension up to QID as needed
Laxative: 2.4 g to 4.8 g (or 30 to 60 mL suspension) daily with water at bedtime

Pediatric Dosing

Antacid (Children 2-11 years): 100 mg to 400 mg oral suspension up to QID
Laxative (Children 6-11 years): 1.2 g to 2.4 g daily at bedtime
Laxative (Children 2-5 years): 0.4 g to 1.2 g daily at bedtime

Indications

Symptomatic relief of hyperacidity, acid indigestion, and heartburn
Short-term treatment of occasional constipation

Mechanism of Action

Reacts with hydrochloric acid in the stomach to form magnesium chloride and water, reducing gastric acidity
Acts as an osmotic laxative in the intestines, drawing water into the lumen, increasing peristalsis, and softening stool

Contraindications

Hypersensitivity to magnesium products
Severe renal impairment (risk of hypermagnesemia)
Undiagnosed abdominal pain, intestinal obstruction, or appendicitis
Fecal impaction or colostomy/ileostomy

Adverse Reactions

Diarrhea and abdominal cramping (dose-related)
Hypermagnesemia (in patients with renal impairment)
Electrolyte disturbances and dehydration (with chronic excessive use)
Nausea and vomiting

Drug Interactions

Decreases absorption of tetracyclines, fluoroquinolones, iron, and ketoconazole via chelation and increased gastric pH
May alter absorption of concurrently administered oral medications; separate dosing by at least 2 hours
May enhance the effects of neuromuscular blocking agents due to magnesium toxicity risk

Curated Content: Needs Vetting Before Put to Clinical Use