Nonsteroidal anti-inflammatory drugs (NSAIDs)

NSAIDs block the cyclooxygenase (COX) enzymes that make prostaglandins, which reduces pain, fever, and inflammation. They treat headaches, muscle and joint pain, arthritis, and menstrual cramps, and low-dose aspirin also keeps platelets from clumping. Stomach upset, ulcers, and bleeding are the main side effects, and they can also raise blood pressure and harm the kidneys. Most carry warnings for heart attack and stroke risk, and aspirin is avoided in children and teens with viral illnesses because of Reye's syndrome.

• AspirinKnown brand names include Bayer Aspirin, Ecotrin, St. Joseph Aspirin, Bufferin, Durlaza, and Vazalore.
• IbuprofenKnown brand names include Advil, Motrin, Ibu, Genpril, Addaprin, Proprinal, and Wal-Profen.