Taking The Pain Out Of Pain Relievers
ORLANDO, May 17, 1999- One of the first examples of a new generation of NSAIDs causes significantly fewer ulcers than do standard non-steroidal anti-inflammatory drugs like ibuprofen, according to data to be presented by a USC scientist today at the plenary session of the American Gastroenterological Association.
In a study of more than 1,500 patients with osteoarthritis who had no signs of ulcers at the beginning of the study, those who took 800 milligrams of ibuprofen three times a day showed significantly more stomach and duodenal ulcers on endoscopic examination than did those who took 50 or 25 milligrams of rofecoxib. "In fact," notes Loren Laine, M.D., USC professor of medicine and lead author on the study, "the ulcer rates with 25 mg. of rofecoxib and with placebo were equivalent."
In addition, previous studies have shown that rofecoxib-at doses a half to a quarter of those given in the current study-is at least as effective as 800 mg. ibuprofen three times a day in relieving osteoarthritis pain, notes Laine.
Rofecoxib is a type of drug called a COX-2 specific inhibitor. Most anti-inflammatory drugs work by blocking cyclooxygenase (COX), an enzyme that plays a role in the production of prostaglandins. Some of the prostaglandins, in turn, are key players in the body's inflammatory response. A drug that turns off cyclooxygenase, then, can also turn off inflammation that results in swollen, painful joints in people with arthritis, for instance.
The problem is, prostaglandins do more than play a role in inflammation. They have myriad roles in the body-for instance, they are also responsible for maintaining the integrity of the stomach lining. That's why drugs that interfere with COX tend to carry a high risk of ulcer formation.
"NSAIDs are really commonly used drugs," says Laine. "But they may cause serious gastrointestinal side effects."
COX-2 inhibitors take advantage of the fact that there are actually two versions of cyclooxygenase found in the body: COX-1 and COX-2. "COX-2 is induced at areas of inflammation," explains Laine, "while COX-1 is involved in the day-to-day maintenance of the stomach lining. What we have seen is that you can get anti-inflammatory effects by inhibiting COX-2, but you decrease or prevent the development of gastrointestinal tract injury by sparing COX-1."
In April, a Food and Drug Administration advisory committee recommended approval of rofecoxib for treatment of osteoarthritis and acute pain. The brand name of rofecoxib will be Vioxx, according to Merck & Co., which manufactures the drug. It is likely that the drug will be approved to treat not only osteoarthritis, but acute pain as well. If given the go-ahead, it will be only the second COX-2 inhibitor on the market.