Proton Pump Inhibitors (PPIs) are a group of very effective and safe medicines used to treat heartburn, gastroesophageal reflux disease (GERD), and ulcers.

But not everyone with heartburn needs one. Several of the PPIs have been widely advertised to consumers and heavily promoted to physicians, and this had led to overuse of the drugs in the treatment of "garden variety" heartburn.

If you suffer from only occasional heartburn and have not been diagnosed with GERD, nonprescription antacids such as Maalox, Mylanta, Rolaids, and Tums, or acid–reducing drugs such as cimetidine (Tagamet), famotidine (Pepcid), nizatidine (Axid), and ranitidine (Zantac) will very likely provide relief.

Talk with your doctor about the role that dietary and lifestyle changes can play in alleviating heartburn, too – such as eating smaller meals, weight loss, and avoiding alcohol.

If, however, you experience heartburn twice a week or more for weeks or months on end, have frequent regurgitation of food into your throat or mouth (with or without heartburn), or if your heartburn is not relieved by the drugs mentioned above, you may have GERD and need a PPI. GERD is a condition that makes you prone to acid reflux and can, over time, cause damage to your esophagus.

The five available PPI medicines are roughly equal in effectiveness and safety, but differ in cost. One – omeprazole (Prilosec OTC) – is available as a prescription and nonprescription generic drug.

Taking the evidence for effectiveness, safety, cost, and other factors into account, Prilosec OTC is our choice as a Consumer Reports Best Buy Drug if you need a PPI. You could save $100 to $200 a month by choosing this medicine over more expensive prescription PPIs.

If you have health insurance, find out if your plan helps pay for Prilosec OTC. If not, talk to your doctor about taking the PPI with the lowest out–of–pocket cost to you.

Safety note: A few studies have linked PPIs to a higher risk of pneumonia and infection with a bacterium called C. difficile, and in December 2006 a study found that long–term use of PPIs may be associated with an increased risk of hip fractures. Talk with your doctor about these risks, especially if you must take a PPI over a long period of time. People aged 65 and over, and people with chronic medical conditions, who take a PPI should get vaccinated against pneumonia and get a flu shot every year.

(1) "Generic" indicates drug sold by generic name, omeprazole.

(2) Monthly cost reflects nationwide retail average prices for September 2006 (except where noted), rounded to nearest dollar. Information derived by Consumer Reports Best Buy Drugs from data provided by Wolters Kluwer Health, Pharmaceutical Audit Suite.

(3) This is a nonprescription (over-the-counter) version of omeprazole available at any drug store. The shelf price of this medicine may vary widely. It may be least expensive at large discount and "big box" stores. The cost for a month's supply given in this table ($19-$26) is based on a spot check of online pharmacies on Oct. 30, 2006.