Heartburn and Indigestion: Antacids, Alginates or a PPI?

Three quite different types of product sit together on the heartburn shelf, and they suit different patterns of symptoms. If you get occasional heartburn after a heavy meal, you need something different from someone who wakes with it four nights a week.

The three options

Antacids (calcium carbonate, magnesium and aluminium salts) neutralise acid that is already there. They work within minutes and wear off within an hour or two. Ideal for occasional, predictable heartburn — the curry, the late meal, the extra glass of wine.

Alginates (usually combined with an antacid) form a raft that floats on the stomach contents and physically blocks reflux. They last longer than a plain antacid and are particularly good for night-time symptoms and reflux in pregnancy. Take after meals and at bedtime.

Proton pump inhibitors such as omeprazole reduce acid production at source. They are the strongest option but take one to four days to reach full effect, so they are not a rescue remedy. A pharmacy course runs for up to 14 days for frequent heartburn.

Antacids can interfere with the absorption of other medicines — including some antibiotics, thyroid medication and iron. Leaving a two-hour gap usually solves it, but check with us if you take regular medication.

The changes that make the biggest difference

• Raise the head of the bed by 10–20cm using blocks under the legs — far more effective than extra pillows, which bend you at the waist and can make reflux worse.
• Leave three to four hours between your last meal and lying down.
• Smaller, more frequent meals rather than one large one.
• Identify your own triggers: common ones are fatty or fried food, spicy food, chocolate, coffee, alcohol, citrus and tomato.
• Losing weight if you carry it around the middle, and stopping smoking, both genuinely reduce reflux.
• Avoid tight waistbands.

Heartburn in pregnancy

Reflux affects a large proportion of pregnancies, particularly later on. Dietary measures and posture come first; if treatment is needed, antacids and alginates are generally the preferred options. Speak to us or your midwife before starting anything, including products you have used before.

When to stop self-treating

See your GP if you have heartburn most days for three weeks or more, or any of the following:

• Difficulty or pain on swallowing, or food sticking
• Unintentional weight loss
• Vomiting blood, or vomit that looks like coffee grounds
• Black, tarry stools
• Persistent vomiting
• A lump in the abdomen or persistent abdominal pain
• Symptoms starting for the first time over the age of 55

Chest pain that is crushing, spreads to the arm, neck or jaw, or comes with breathlessness or sweating is not heartburn until proven otherwise — call 999.

Frequently asked questions