Ibuprofen is a non-steroidal anti-inflammatory drug (NSAID) used for its analgesic, antipyretic and anti-inflammatory properties. Like most NSAIDs, ibuprofen is a non-selective inhibitor of prostaglandin G/H synthase 1 and 2, better known as cyclooxygenase 1 and 2 or simply COX-1 and -2. COX catalyzes the conversion of arachidonic acid to a number of prostaglandins involved in fever, pain, swelling, inflammation, and platelet aggregation. Ibuprofen antagonizes COX by binding to the upper portion of the active site, preventing its substrate, arachidonic acid, from entering the active site. The analgesic, antipyretic and anti-inflammatory effects of ibuprofen occurs as a result of decreased prostaglandin synthesis. Ibuprofen is slightly more potent than aspirin and produces analgesic effects at lower doses than aspirin. Unlike aspirin, ibuprofen is a reversible COX inhibitor and thus it is not used as an antiplatelet agent.