DIFFERENT WAYS TO SPELL RELIEF

By LEON JAROFF

IT'S A FEELING ALL TOO FAMILIAR TO MILLIONS OF AMERICANS, AN UNCOMfortable, burning sensation that begins in the chest and neck after a meal. The burning is real, caused by acid being regurgitated into the esophagus from the stomach. It occurs when a muscular valve, which should be tightly closed except when food is swallowed, relaxes or operates inefficiently, allowing stomach contents to back up. In other parts of the world, most people accept it as a fact of life--and tough it out. In the U.S., says Dr. John Walsh, former president of the American Gastroenterological Association (A.G.A.), "only a fraction of people with heartburn take antacids or other treatments. Now companies are telling consumers that this is something they ought to treat."

What separates the new over-the-counter medications from the old solutions? Antacids, which consist largely of chemical compounds called bases, neutralize the wayward acid, but as acid continues to migrate upward from the stomach, heartburn can return in only a few hours. Acid blockers like Pepcid and Tagamet, on the other hand, go to the root of the problem by suppressing the production of acid in cells lining the interior of the stomach without interfering with normal digestion. These cells normally produce acid when a form of histamine called H2 "docks" with receptors in the cell walls, much like a key fitting into a lock. But acid blockers, called H2 antagonists, prevent that production by seeking out and fitting snugly into the stomach cell receptors, denying access to H2. Depending on the size of the drug dosage, acid production can be curtailed for as long as 12 hours.

But is the bigger bang provided by H2 antagonists worth the much bigger buck to the consumer? And does it justify the FDA's approval of over-the-counter versions? When the FDA discussed the issue, an analogy to over-the-counter arthritis medication was forcefully made: Just as some people need effective, readily available medicine for aches and pains, some people need similar medicine for heartburn.

As for side effects, two studies last week showed that both antacids and H2 blockers may mask symptoms of bleeding ulcers among people with rheumatoid arthritis. These patients often take the pills thinking they will relieve bleeding that can occur with high doses of rheumatoid-arthritis drugs like ibuprofen. While neither H2 antagonists nor antacids cause bleeding, they may keep those with ulcers from recognizing the need to seek help. H2 blockers still have fewer side effects than antacids. (Tagamet may interfere with the body's ability to metabolize certain drugs, but the incidence, say researchers, is not significant.) Meanwhile, calcium-based antacids like Tums and Rolaids can occasionally contribute to kidney stones, and aluminum- and magnesium-based ones like Mylanta and Maalox can sometimes be dangerous for people with kidney problems. Says clinician Dr. Thomas Gage, a member of the A.G.A.'s patient-care committee: "The risk-benefit profile for H2 blockers is excellent, and they represent an advance over what was previously available."

--Reported by Lawrence Mondi/New York

With reporting by Lawrence Mondi/New York