Nonsteroidal anti-inflammatory drugs are drugs which have analgesic and antipyretic effects and in higher doses, anti-inflammatory effects.The most common drugs of this group of drugs are aspirin, ibuprofen, and naproxen.Most NSAIDs act as nonselective inhibitors of the enzyme cyclooxygenase (COX), inhibiting both the cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) isoenzymes. COX catalyzes the formation of prostaglandins and thromboxane from arachidonic acid. Prostaglandins act as messenger molecules in the process of inflammation.The COX-3 pathway was believed to fill some of this gap but recent findings make it appear unlikely that it plays any significant role in humans and alternative explanation models are proposed.
NSAIDS have antipyretic activity and can be used to treat fever.Fever is caused by elevated levels of prostaglandin E2, which alters the firing rate of neurons within the hypothalamus that control thermoregulation.Antipyretics work by inhibiting the enzyme COX, which causes the general inhibition of prostanoid biosynthesis (PGE2) within the hypothalamus.PGE2 signals to the hypothalamus to increase the body's thermal set point.Ibuprofen has been shown to be more effective as an antipyretic than acetaminophen.
Most NSAIDs are metabolised in the liver by oxidation and conjugation to inactive metabolites which are typically excreted in the urine, although some drugs are partially excreted in bile. Ibuprofen and diclofenac have short half-lives (2–3 hours).