You might call them pain relievers. You might take them for back pain, headache, or arthritis. Your doctor calls them “NSAIDs,” which stands for nonsteroidal anti-inflammatory drugs. Whatever you call them and for whatever reason you take them, NSAIDs are among the most popular medications worldwide. In fact, estimates suggest that about 15% of the US population takes an NSAID regularly (including those that are over the counter and prescription strength). Along with sporadic users, more than 30 billion doses are taken each year. Some of the most common NSAIDs include ibuprofen (as in Motrin), naproxen (as in Aleve) and celecoxib (as in Celebrex).