Magnesium hydroxide

Oral
Constipation
Adult: For relief of occasional cases: As 400 mg/5 mL or 1,200 mg/15 mL suspension: 30-60 mL. As 2,400 mg/10 mL: 15-30 mL. All doses may be taken once daily (preferably at bedtime) or in divided doses, or as directed. As 800 mg/5 mL suspension: 10-20 mL once daily (preferably at bedtime). Drink a full glass of water with each dose. As 1,325 mg/5 mL paste concentrated suspension: 25-50 mL diluted in a glass of water to be taken at bedtime. Dosage recommendations may vary among countries and individual products (refer to specific product guideline).
Child: For relief of occasional cases: 2-<6 years As 400 mg/5 mL or 1,200 mg/15 mL suspension; 400 mg chewable tablet: 400-1,200 mg daily as single or in divided doses (Max: 1,200 mg/day). As 800 mg/5 mL suspension: 800 mg once daily (preferably at bedtime) or as directed. 6-<12 years As 400 mg/5 mL or 1,200 mg/15 mL suspension; 400 mg chewable tablet: 1,200-2,400 mg daily as single or in divided doses (Max: 2,400 mg/day). As 800 mg/5 mL suspension: 800-1,600 mg once daily (preferably at bedtime). Drink a full glass of water with each dose. ≥12 years Same as adult dose. Dosage recommendations may vary among countries and individual products (refer to specific product guideline).
Renal impairment: Severe renal failure: Contraindicated.

Oral
Hyperacidity
Adult: For the relief of heartburn, indigestion or upset stomach: As 400 mg/5 mL suspension: 5-15 mL up to 4 times daily, or as directed. As 2,400 mg/10 mL suspension: 5 mL. Max: 20 mL in 24 hours. Doses may be taken with water. As 1,325 mg/5 mL paste concentrated suspension: 5-10 mL diluted in small amount of water, as necessary. Dosage recommendations may vary among countries and individual products (refer to specific product guideline).
Child: ≥12 years Same as adult dose.
Renal impairment: Severe renal failure: Contraindicated.

Susp: Should be taken on an empty stomach. Take 1 hr after meals & at bedtime.

Acute gastrointestinal conditions; severe renal failure.

Patients with myasthenia gravis or neuromuscular disease, sudden change in bowel habits (which persists for >2 weeks), Mg-restricted diet; stomach pain, nausea or vomiting. Debilitated patients. Renal and hepatic impairment. Children and elderly. Pregnancy and lactation.

Significant: Rarely, hypermagnesaemia (particularly in patients with renal impairment). Gastrointestinal disorders: Abdominal pain, diarrhoea (dose-dependent), colic.

Symptoms: Watery diarrhoea, gastrointestinal irritation; rarely, hypermagnesaemia which includes symptoms such as nausea, vomiting, thirst, flushing, drowsiness, hypotension, confusion, loss of tendon reflexes, muscle weakness, respiratory depression, cardiac arrhythmias, cardiac arrest and coma. Management: Administer Ca gluconate 10% 10-20 mL via IV to counteract respiratory depression or heart block. May give adequate fluids to patients with normal renal function to aid removal of Mg in the body. May perform haemodialysis in patients with renal impairment or severe hypermagnesaemia.

May decrease absorption of certain antibiotics (e.g. cefpodoxime, tetracyclines, quinolones), antifungals (e.g. itraconazole), antivirals (e.g. atazanavir, rilpivirine), fexofenadine, bisphosphonates (e.g. alendronic acid, ibandronic acid), corticosteroids (e.g. dexamethasone, deflazacort), antiepileptics (e.g. gabapentin, phenytoin), certain antipsychotics (e.g. sulpiride, chlorpromazine), ACE inhibitors (e.g. captopril), rosuvastatin, chloroquine, hydroxychloroquine, proguanil, digoxin, dipyridamole, levothyroxine, mycophenolate, iron preparations, nilotinib, and penicillamine. May increase absorption of ibuprofen. May decrease the excretion of quinidine. May enhance the adverse or toxic effect, particularly metabolic alkalosis, of sodium polystyrene sulfonate. Excretion of salicylates may be increased.

Magnesium hydroxide stimulates bowel movement by retaining fluid in the intestinal lumen which distends the colon, thus increasing peristalsis. It also neutralises stomach acid by reacting with hydrochloric acid in the stomach to form Mg chloride.
Onset: Bowel movement: 30 minutes to 6 hours.
Absorption: Mg: Poorly absorbed from the small intestine (approx 30%).
Distribution: Mg: Crosses the placenta; enters breast milk (small amounts).
Excretion: Mainly via urine (up to 30% as absorbed Mg ions); faeces (as unabsorbed drug).

Oral: Store below 25°C. Do not freeze.

Antacids, Antireflux Agents & Antiulcerants / Laxatives, Purgatives

G04BX01 - magnesium hydroxide ; Belongs to the class of other urologicals.
A02AA04 - magnesium hydroxide ; Belongs to the class of magnesium-containing antacids.