Non-steroidal anti-inflammatory drugs (NSAIDs)
Most drugs of the group of non-steroidal anti-inflammatory drugs (NSAIDs), or prostaglandin synthase inhibitors, are non-specific COX inhibitors. These drugs inhibit allisoforms of the cyclo-oxygenase enzyme: COX-1, COX-2, and COX-3. They thus inhibit the conversion of arachidonic acid into prostaglandins. These drugs are used to inhibit pain stimuli (decrease pain intensity) and to lower inflammatory reactions and fever.
The non-specific nature of these drugs is responsible for most of the side effects. Because conventional NSAIDs also inhibit COX-1, general household functions like protection of the gastrointestinal tract, renal perfusion and platelet function are disturbed. Consequently, peptic ulcus can develop and/or renal function can diminish. Since both, COX-1 and COX-2 influence platelet function in opposite way, the use of non-specific COX inhibitors usually does not result in side effects such as arterial thrombosis etc.
In order to control the pain of a patient with peptic ulcer, aspirin is first choice.
Physiological concentrations of prostaglandins do NOT cause pain.