Non-steroidal anti-inflammatory drugs (NSAIDs) are non-prescription, over-the-counter pain relievers such as aspirin, ibuprofen, and naproxen sodium. They are popular treatments for muscular aches and pains, as well as arthritis.

NSAIDs not only relieve pain, but also help to decrease inflammation, prevent blood clots, and reduce fevers. They work by blocking the actions of the cyclooxygenase (COX) enzyme. There are two forms of the COX enzyme. COX-2 is produced when joints are injured or inflamed, which NSAIDS counteracts.

COX-1 protects the stomach lining from acids and digestive juices and helps the kidneys function properly. This is why the side effects of NSAIDs may include nausea, upset stomach, ulcers, or improper kidney function.