There are 4 major classes of drugs to treat the acid element of acid reflux.

In ascending order of effectiveness, they are antacids, alginates, H2 blockers and Proton Pump Inhibitors.

If you need to use any of these drugs frequently,

please seek medical advice.


They work immediately on excess acid. They do not prevent excess acid occurring.

These are drugs that neutralise the acid. Most commonly they are made of chalk, calcium carbonate. Examples are Tums or Rennie. Chemically, this reaction takes place:

CaCO3 + 2HCl → CaCl2 + H2O + CO2

(Calcium Carbonate + Hydrochloric acid gives Calcium Chloride (a harmless salt) plus water and carbon dioxide) as shown in the Rennie advertisement below:


Gaviscon is the brand name of the white milky liquid that floats on the stomach contents as oil floats on water to reduce the possibility of reflux whilst also providing a temporary protective film to the lower oesophagus and neutralising the acid with an antacid component. (Some generic versions are now available.)

Gaviscon NHS cost for 28 days


H2 blockers

Histamine H2 Receptor Antagonists work to block the (histamine H2) signals that tell the stomach to produce acid. (N.B. This is not the same as an antihistamine which blocks histamine H1).

The most common is Ranitidine, brand name Zantac but others are available as shown below.

These work proactively to reduce the amount of acid rather than being an instant antacid. Often prescribed to be taken in the evening to reduce nighttime reflux of acid.

H2 blockers

    • (Other H2 blockers: Lafutidine, Loxtidine, Niperotidine, Roxatidine.)

* Please note doses shown are not guaranteed to be equivalent. Do not assume because a dose is shown it is the safe dose. It may vary according to age and body build.

Proton Pump Inhibitors (PPIs)

These are the most effective drugs to reduce acid production. They work by effectively turning off some of the cells (proton pumps) that produce acid in the stomach.

There are a number known by different names as shown in the table below. The equivalent dose shown is the "maintenance dose" though you may be prescribed a higher dose initially. They are proactive drugs and are most effective after taking them for a few days. They do not neutralise acid already produced.

Many people claim PPIs are dangerous. Read this page, PPI dangers, and decide for yourself.

PPI (Proton Pump Inhibitor) drugs

(Other PPIs: Ilaprazole, Picoprazole, Tenatoprazole, Timoprazole)

Do not assume because a dose is shown it is the safe dose. It may vary according to age and body build.

The most common brand names are shown though they may also be known under other names in other parts of the world.

Research evidence has shown all PPIs are as effective as each other (though the drugs companies may try to make us believe otherwise) but some may be better tolerated by some patients. (A copy of this may be downloaded at the bottom of this page.)

An evaluation report from 2009 may be found by clicking here.

* Astra Zeneca (who make the drug) claims 40mg esomeprazole is equivalent to 20mg omeprazole and one (Astra Zeneca sponsored) trial showed 40mg esomeprazole was better at reducing acid production than 20mg omeprazole. Available here.

Another study sponsored by Astra Zeneca published February 2015 also compared 40mg esomeprazole with 30mg lasoprazole and 40mg Pantoprazole finding: "esomeprazole was more effective".

And yet another study sponsored by Astra Zeneca in November 2015 showed 20mg esomeprazole "significantly better" than omeprazole, pantoprazole and lansoprazole at currently available OTC dosages - which are half the esomeprazole equivalnt dose.

This latter finding was counteracted by a comparative study (not sponsored by Astra Zeneca) that found "There was no significant difference in the therapeutic success between omeprazole and S-omeprazole"

Research funded by Reckitt Benkiser (who make the drug) found Gaviscon was no less effective than standard dose omeprazole for a 24hr period. Available here.

For our American visitors, this table shows US prices, thanks to ConsumerReports.org:

1. Consumer Reports Best Buy Drugs report, July 2013.