New painkillers may damage stomach lining

A class of recently developed painkiller drugs that also are being used to help prevent cancer may damage linings in the stomach and intestine in people with ulcers and other gastrointestinal damage, a team of UC Irvine College of Medicine researchers has found.

The drugs, called "Cox-2 inhibitors," were developed to treat pain without causing the stomach ulcers and other gastrointestinal side effects often caused by long-term use of aspirin, ibuprofen and other drugs used to treat arthritis and pain.

Cox-2 inhibitors were the most widely prescribed new drug in the country during 1999. So far, more than 12 million prescriptions have been written. The drugs increasingly are being used as cancer prevention agents.

But, writing in the December 1999 issue of Nature Medicine, researchers found that Cox-2 inhibitors halted the formation of tiny blood vessels that normally induce ulcer healing and help the body recover from injury.

The research team was led by Dr. Andrzej Tarnawski, professor and chief of gastroenterology at UCI and the Department of Veterans Affairs Medical Center in Long Beach, Calif.

"Although Cox-2 inhibitors were designed as a drug that would not cause ulcers and damage seen with aspirin and related drugs, we found that they still can produce side effects by delaying healing of ulcers and other intestinal wounds," Tarnawski said. "This finding raises concerns about prescribing them to patients with existing gastrointestinal problems like gastric ulcers and erosion of the lining protecting the gastrointestinal tract."

Cox-2 inhibitors, aspirin and ibuprofen belong to a group of drugs called non-steroidal anti-inflammatory drugs (NSAIDs), which are the most commonly used drugs in the United States.

In addition to treating pain, NSAIDs inhibit a cellular process called angiogenesis, the formation of tiny new blood vessels. Angiogenesis is essential for wound and ulcer healing, restoring blood flow, oxygen and nutrients to wounds.

Scientists say that blocking this process may lead to the side effects caused by long-term use of NSAIDs, especially in patients with existing ulcers and other intestinal problems. Cox-2 inhibitors were developed because aspirin and other non-Cox-2 drugs cause ulcers and other gastrointestinal damage in 60% of users.

In addition, angiogenesis is essential for cancerous tumors to grow and spread through the body. Recently, scientists have been exploring the role of Cox-2 inhibitors and other NSAIDs in preventing cancer. Halting angiogenesis may stop the growth of cancer, but it also can prevent the processes necessary for wound healing, causing ulcers to form.