Antacid (Aluminium + Magnesium Hydroxide): Uses, Side Effects & Safety

What it is and what it's used for

Antacid (aluminium + magnesium hydroxide) is a combination antacid — a medicine that neutralises excess acid in the stomach. Aluminium hydroxide and magnesium hydroxide are two well-known antacid ingredients, and combining them balances their effects: the aluminium part can cause constipation, while the magnesium part can cause loose motions, so together they tend to cancel each other out.

In India it is used for short-term relief of heartburn, acidity, indigestion, sour stomach, and the gnawing stomach pain of gastritis. It is available over the counter (OTC) without a prescription. It only relieves symptoms — it does not heal ulcers or cure the underlying cause of acidity.

How it works (simple language)

The stomach normally makes acid to digest food. When too much acid is made, or acid flows back into the food pipe, it causes the burning feeling of heartburn and acidity. Aluminium hydroxide and magnesium hydroxide are mild bases — the opposite of acids. When swallowed, they react with the stomach acid and neutralise it, raising the pH of the stomach contents and quickly easing the burning and pain. They also form a light coating over the stomach lining, which soothes irritation. Relief usually comes within minutes of taking a dose.

Dosage forms available in India (general info only)

Antacid (aluminium + magnesium hydroxide) is commonly available in India as chewable tablets and as a liquid suspension (syrup), often with added simethicone for gas. Well-known Indian brands include Gelusil and Digene, though brands and pack sizes vary from shop to shop.

Never decide the dose yourself from this article. Always follow your doctor's prescription or the directions on the pack, and check with your pharmacist if you are unsure — especially for children, where the dose depends on the child's weight and age.

Side effects

Common: Chalky or unpleasant taste, mild nausea, constipation from the aluminium part, loose motions from the magnesium part, and mild stomach cramps. These are usually short-lived and settle on their own.

Serious — seek medical care: Stop use and seek medical help if you notice black or tarry stools, vomit that looks like coffee grounds, severe or ongoing stomach pain, blood in the stool, unexplained tiredness with pale skin, or — in people with kidney disease — confusion, muscle weakness, or a very slow heartbeat, which can signal mineral build-up from long-term use.

Precautions and warnings

• Not a long-term solution. Needing antacid every day for weeks may hide a serious condition like an ulcer; if symptoms persist beyond 2 weeks, see a doctor.
• Kidney disease caution. People with kidney problems can build up excess magnesium or aluminium in the blood; use only on a doctor's advice.
• Keep a gap from other medicines. Antacids can block the absorption of many medicines — take them at least 2 hours before or after other medicines.
• Children. Use in children only as advised by a doctor, with the dose based on the child's age and weight.
• Heartburn vs heart attack. Severe chest pain, pain spreading to the arm, neck or jaw, sweating, or breathlessness should be treated as an emergency — do not assume it is acidity.
• Check the pack. Do not exceed the maximum number of doses per day printed on the pack.
• Pregnancy. Often used for pregnancy heartburn, but always consult your doctor first and avoid prolonged use.

Interactions (general)

Antacids can reduce how well many medicines are absorbed, including certain antibiotics (such as tetracyclines and fluoroquinolones like ciprofloxacin), iron supplements, and thyroid medicine (levothyroxine). Keep a gap of at least 2 hours (some doctors advise 4) between the antacid and any other medicine. Alcohol and smoking can worsen acidity and may slow recovery. Always tell your doctor about ALL medicines you take, including herbal and ayurvedic products.

Pregnancy and breastfeeding (general guidance)

Antacids containing aluminium and magnesium are often used for heartburn during pregnancy because very little is absorbed into the blood, but the safest course is to consult your doctor first. Avoid high doses or prolonged use, especially in the third trimester, and do not use them while breastfeeding without medical advice.

Storage

Store at room temperature in a cool, dry place, away from direct sunlight. Keep the bottle tightly closed and shake the suspension well before use. Keep all medicines out of the reach of children, and do not use the product after its expiry date.

When to see a doctor

See a doctor if: heartburn or acidity happens more than twice a week; antacids stop working or you need increasing amounts; you have black stools, vomiting blood, unexplained weight loss, difficulty swallowing, or pain spreading to the arm, neck or jaw (seek emergency care for these). Persistent acidity may need proper diagnosis and different treatment.

FAQs

1. How quickly does antacid work?

Usually within a few minutes of taking a dose. Liquid suspensions tend to act slightly faster than tablets. Chewable tablets should be chewed completely before swallowing so they can coat and neutralise acid properly.

2. Can I take antacid every day for a long time?

It is not meant for long-term daily use. Frequent or worsening acidity may point to gastritis, an ulcer, or reflux disease that needs a doctor's diagnosis and different treatment. If you need antacid regularly for more than 2 weeks, see a doctor.

3. Can I take antacid together with my other medicines?

Many medicines are absorbed poorly when taken with antacids. As a rule, take antacid at least 2 hours before or after your other medicines, and tell your doctor about everything you take, including herbal and ayurvedic products.

4. Is antacid safe during pregnancy?

It is commonly used for pregnancy heartburn because very little enters the bloodstream, but always consult your doctor first. Avoid high doses or daily long-term use during pregnancy unless your doctor advises it.