Non-steroidal anti-inflammatory drugs, usually abbreviated to NSAIDs or NAIDs, are drugs with analgesic, antipyretic (lowering an elevated body temperature and relieving pain without impairing consciousness) and, in higher doses, with anti-inflammatory effects (reducing inflammation). The term "non-steroidal" is used to distinguish these drugs from steroids, which (among a broad range of other effects) have a similar eicosanoid-depressing, anti-inflammatory action. As analgesics, NSAIDs are unusual in that they are non-narcotic.

NSAIDs are sometimes also referred to as non-steroidal anti-inflammatory agents/analgesics (NSAIAs) or non-steroidal anti-inflammatory medicines (NSAIMs). The most prominent members of this group of drugs are aspirin, ibuprofen, and naproxen partly because they are available over-the-counter in many areas.

Mechanism of action

Most NSAIDs act as non-selective inhibitors of the enzyme cyclooxygenase, inhibiting both the cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) isoenzymes. Cyclooxygenase catalyzes the formation of prostaglandins and thromboxane from arachidonic acid (itself derived from the cellular phospholipid bilayer by phospholipase A₂). Prostaglandins act (among other things) as messenger molecules in the process of inflammation. This mechanism of action was elucidated by John Vane, who later received a Nobel Prize for his work (see Mechanism of action of aspirin). A newly discovered COX-3 may also have some role.

Examples

NSAIDs can be broadly classified based on their chemical structure. NSAIDs within a group will tend to have similar characteristics and tolerability. There is little difference in clinical efficacy among the NSAIDs when used at equivalent doses. Rather, differences among compounds tended to be with regards to dosing regimens (related to the compound's elimination half-life), route of administration, and tolerability profile. Some more common examples are given below.

COX-2 inhibitors

• Celecoxib (FDA alert )
• Etoricoxib FDA withdrawn
• Lumiracoxib TGA cancelled registration
• Parecoxib FDA withdrawn
• Rofecoxib (withdrawn from market )
• Valdecoxib (withdrawn from market )

Sulphonanilides

• Nimesulide (banned by several countries for the potential risk of hepatotoxicity)

Others

• Licofelone
• Omega-3 fatty acids

Licofelone acts by inhibiting LOX (lipooxygenase) & COX (cyclooxygenase)and hence known as 5-LOX/COX inhibitor.

Uses

NSAIDs are usually indicated for the treatment of acute or chronic conditions where pain and inflammation are present. Research continues into their potential for prevention of colorectal cancer, and treatment of other conditions, such as cancer and cardiovascular disease.