New research could help cut cardiovascular risks associated with arthritis drugs

Researchers may be on their way to finding safer drugs for treating arthritis that don't cause potentially harmful cardiovascular side effects like some past and current medications.

Arthritis drugs like Vioxx, diclofenac, ibuprofen and Celebrex have been linked to an increased risk of heart attack or stroke, and safety concerns lead to Vioxx manufacturer Merck ($MRK) pulling the drug from the market in 2004. Recently, the European Medicines Agency also has advised patients with underlying heart conditions to stop using the painkiller diclofenac due to a small increased risk of heart attack and stroke.

Vioxx, diclofenac, ibuprofen and Celebrex work by blocking an enzyme known as COX-2, previously thought to be found in the blood vessels where it helped prevent the formation of clots. Scientists believed that drugs that inhibited COX-2 would increase the risk of clotting. But researchers at Imperial College London have now discovered that in mice, COX-2 is largely absent from the major blood vessels and is instead present in the brain, kidney, thymus and gut, where it might be affecting cardiovascular health.

"Now we know the true sites of COX-2, we can begin to develop new ideas that will lead to better drugs for arthritis and cancer with fewer side effects," said lead study author Jane Mitchell of Imperial's faculty of medicine. 

The findings, which identify where in the body arthritis drugs act, could help scientists develop COX-2 inhibitors that carry less risk of stroke or heart attack for patients. The research, funded by the Wellcome Trust, will appear in the online journal PLoS One.

- here's the press release
- and the PLoS ONE study