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 more effective as an antipyretic than paracetamol (acetaminophen).   Arachidonic acid is the precursor substrate for cyclooxygenase leading to the production of prostaglandins F, D & E.
Two studies compared different types of non-selective NSAIDs, namely ibuprofen versus diclofenac and piroxicam versus indomethacin. The trials did not find any differences between these NSAID types, but both trials had small sample sizes. One trial reported no differences in pain intensity between treatment groups that used selective or non-selective NSAIDs. One other trial compared diflunisal with paracetamol and showed no difference in improvement from baseline on pain intensity score. One trial showed a better global improvement in favour of celecoxib versus tramadol.
Six of the 13 included RCTs showed that NSAIDs are more effective than placebo regarding pain intensity. NSAIDs are slightly more effective than placebo regarding disability. However, the magnitude of the effects is small, and the level of evidence was low. When we only included RCTs at low risk of bias, differences in effect between NSAIDs and placebo were reduced. We identified no difference in efficacy between different NSAID types, including selective versus non-selective NSAIDs. Due to inclusion of RCTs only, the relatively small sample sizes and relatively short follow-up in most included trials, we cannot make firm statements about the occurrence of adverse events or whether NSAIDs are safe for long-term use.