Drug makers, eyeing Viagra's runaway success with profit envy, expect the drive for arthritis relief will yield the next wonder drug.

Some industry experts believe Celebra, a painkiller that cuts inflammation but avoids the stomach-damaging effects of aspirin, ibuprofen and acetaminophen, could outsell the impotency drug by millions of dollars a year.Drug makers' ceaseless efforts to stock America's medicine chest have long plowed research money into trying to ease such ills as cancer, obesity and chronic pain. But the road to a cancer cure is littered with promising treatments that fizzled. And last year's recall of two diet pills left many dieters wary of weight-loss drugs.

Now comes a new class of super painkillers with a singular advantage: They could be on pharmacy shelves within months. And industry watchers believe millions of Americans will gladly toss their bottles of common painkillers for an alternative that saves their stomachs.

Kathryn Howe already has.

Rheumatoid arthritis left the 51-year-old executive secretary's joints so swollen she couldn't type or take long walks. Rolling over in bed hurt.

She kept the swelling under control with prescription-strength versions of drugs such as Tylenol and Advil. But 15 years of them left her with an inflamed stomach and rectal bleeding. Last year, her doctor asked her to test an unapproved drug called Celebra. Now she walks, swims, does low-impact aerobics and even lifts weights comfortably with no apparent side effects.

"A person can shake my hand and I'm not in pain," the Eastlake, Ohio, resident said. "I can hold a pencil."

Some analysts predict Celebra will outsell Viagra, the lucrative Pfizer Inc. impotency treatment that became the fastest-selling drug in history its first month.

"That's what I would put my finger on as the next blockbuster drug, not only in terms of medicinal value but in terms of cult following," said Stephen Tang, a drug industry specialist with A.T. Kearney, a management consulting firm in New York.

Typical estimates call for annual Viagra sales to reach $3 billion by 2002. Celebra sales could eventually top $4 billion, said Salomon Smith Barney analyst Christina Heuer.

With the global market for prescription painkillers, not including over-the-counter sales, at $5 billion, Heuer predicts Celebra could be "the most significant new drug introduction of 1999."

Celebra is expected to be the first out of the blocks from a new class of drugs called cox-2 inhibitors, so named because they block the inflammatory enzyme cyclooxygenase.