Results of a US study suggest that drugs called proton pump inhibitors (PPIs) are just as effective as histamine-2 receptor antagonists (H2RAs) for suppressing stomach acid production among heartburn patients during the first day of treatment.

Writing in the journal Alimentary Pharmacology & Therapeutics, Dr Philip Miner Jr, from the University of Oklahoma Health Sciences Center, in Oklahoma City, and colleagues explain that PPIs are generally considered to have a slower mode of action than H2RAs, with the former reaching full effectiveness after 5 days of treatment.

"Thus, little direct comparison data exists between H2RAs and PPIs for gastric acid suppression on day 1 of therapy," they explain.

To address this, the researchers enrolled 31 heartburn patients in a 14-day study of three over-the-counter treatments. These included the PPI omeprazole magnesium 20.6 mg once a day, the H2RA famotidine 10 mg twice a day and famotidine 20 mg twice a day.

Tests revealed that, compared with both doses of the H2RA, treatment with the PPI produced similar levels of stomach acid suppression on day 1 of treatment.

However, after day 1, the PPI was consistently more effective than both doses of the H2RA at suppressing stomach acid production among the participants.

Indeed, the effectiveness of the lower-dose H2RA at suppressing stomach acid production fell significantly after the first day of use.

However, the researchers stress that their study did not measure symptom relief or speed of action of the different drugs.

Dr Miner commented: "Because these two drugs work in fundamentally different ways to suppress acid production, we didn't expect that the PPI would work as well as the H2RAs within the first 24-hour period after treatment."

He concluded: "The study results add an important aspect to the existing literature on these two medications.

"It further underscores the need for consumers to identify their needs in heartburn protection in order to select the most appropriate treatment."