Digestive health · Antacid
Antacid (aluminium / magnesium hydroxide)
A combination antacid used for fast, short-term relief of heartburn, indigestion, and mild acidity.
OTCKidney warningAlcohol interactionNot for young childrenSenior precautionOverview & typical uses
A combination antacid used for fast, short-term relief of heartburn, indigestion, and mild acidity.
Primary uses
- Fast temporary relief of heartburn and indigestion
- Relief of mild acidity or sour burping after meals
How it works
Neutralises stomach acid on contact, giving relief within minutes but for a shorter time than acid-reducers such as PPIs.
Available forms & strengths
- Chewable tablet (Oral)
- Oral suspension (Oral)
General precautions & contraindications
Do not use if
- Known allergy to any ingredient
- Severe kidney disease (for aluminium/magnesium salts)
Pregnancy
Generally considered safe. Occasional use is generally acceptable; avoid sodium-heavy antacids in high blood pressure.
Breastfeeding
Generally considered safe. Compatible with breastfeeding at typical amounts.
Kidney considerations
- Aluminium-containing antacids can accumulate in kidney disease — discuss with a clinician.
Paediatric use
Not for regular use in young children without clinical guidance.
Older adults
Watch for interactions with other regular medicines.
Common side effects
- Mild constipation (aluminium salts) or mild diarrhoea (magnesium salts)
- Bloating or belching
Serious warnings — seek help if these appear
- Serious allergic reaction (very rare)
- Electrolyte imbalances with large chronic use
Drug interactions
Reduces absorption — separate doses by 2 to 4 hours.
Reduced absorption — separate doses.
May slightly reduce absorption.
Food & alcohol precautions
May slightly reduce antacid effect.
Alcohol
- Alcohol can worsen reflux symptoms.
Storage, missed dose & overdose
Storage
Store below 25 °C, out of reach of children.
If a dose is missed
Take as needed for symptoms; no strict schedule.
Overdose
Excessive use can cause electrolyte imbalance. Seek medical advice for large repeated use.
Frequently asked questions
Antacids act within minutes for occasional heartburn. Omeprazole (PPI) takes longer to work but is better for frequent symptoms.
Medical references
- British National Formulary — Antacids — BNF (NICE)
- WHO Model Formulary — World Health Organization
Content last reviewed: 2025-01-01
Medical disclaimer
This information is for educational purposes only and should not replace professional medical advice. Please consult a licensed pharmacist or clinician for advice tailored to your personal circumstances.