Indications
Magnesium Hydroxide Dried Gel, 96% is a dried, powdered form of magnesium hydroxide containing at least 96% of the active substance, used by manufacturers to prepare oral medicines. It is the active ingredient of milk of magnesia type oral suspensions and emulsions. Magnesium hydroxide is used for the short-term relief of constipation, and in smaller doses as an antacid to relieve indigestion, heartburn and acid stomach.
How It Works
As an antacid, magnesium hydroxide reacts with stomach acid and neutralises it, easing burning and discomfort. As a laxative, the magnesium that stays in the bowel draws water into it by osmosis, softening the stool and increasing bowel movement. A laxative dose usually works within 30 minutes to 6 hours.
Dosage and Administration
Use the finished medicine as directed on its label. For the common suspension containing about 400 mg magnesium hydroxide in 5 ml, adults usually take:
- For indigestion: 5 to 10 ml up to 4 times a day, between meals and at bedtime.
- For constipation: 30 to 45 ml at bedtime, followed by a glass of water.
Shake well before use. Children’s doses depend on age: follow the label or a doctor’s advice. Do not use as a laxative for more than 1 week without medical advice.
Interactions
Magnesium hydroxide can reduce the absorption of many medicines, including Tetracycline and Doxycycline, Ciprofloxacin and Levofloxacin, Iron, Levothyroxine, Alendronate, Digoxin, Gabapentin and some HIV medicines. Take other medicines at least 2 hours before or 4 hours after it. It can also damage the coating of enteric-coated tablets if taken at the same time.
Contraindications
- Severe kidney disease (magnesium can build up in the blood).
- Bowel obstruction, appendicitis or unexplained stomach pain, nausea or vomiting.
- Severe dehydration.
Side Effects
Diarrhoea and stomach cramps are the most common effects, especially at higher doses. Long-term or heavy use can upset salt balance, and in people with kidney problems can cause high magnesium levels.
Get urgent medical help if you have severe or persistent diarrhoea, rectal bleeding, or signs of high magnesium such as muscle weakness, drowsiness, confusion, very low blood pressure or a slow heartbeat.
Pregnancy and Lactation
Occasional use at usual doses is considered acceptable during pregnancy and breastfeeding, as little is absorbed. Ask a doctor or pharmacist before regular use.
Precautions and Warnings
- See a doctor if indigestion lasts more than 2 weeks, or if you have difficulty swallowing, weight loss, vomiting or black stools.
- See a doctor if constipation lasts more than 1 week or bowel habits change suddenly.
- People with kidney disease or on a low-magnesium diet should ask a doctor first.
Overdose
Overdose causes diarrhoea and dehydration, and rarely high blood magnesium (especially with kidney disease), leading to weakness, drowsiness and low blood pressure. Contact a doctor promptly.
Therapeutic Class
Antacid and osmotic laxative (magnesium salt).
Storage
Store below 30°C in a tightly closed container, away from light. Do not freeze. Keep out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.