Benefits and risks. By acting only on COX-2 enzymes, they allow COX-1 enzymes to continue to function. COX-1 enzymes protect the lining of the stomach. NSAIDs, on the other hand, block COX-1 and can cause side effects such as thinning of the stomach lining. This can lead to ulcers and bleeding.
The risk of stomach bleeding tends to be lower if you take a COX-2 inhibitor, but bleeding can still occur. This is true especially at higher doses. And COX-2 inhibitors can lead to headaches, dizziness, high blood pressure, kidney problems, fluid retention and high blood pressure. These medications may increase the risk of a heart attack or stroke.