We identified 18,326 cases of hyperkalemia and 355,106 matched controls. Risk of hyperkalemia did not differ in patients using a single NSAID (adjusted OR, ; 95% CI, -) or 2 or more NSAIDs (OR, ; 95% CI, -) compared with patients no longer using an NSAID. However, risk varied by specific NSAID and elevated risks were found for use of rofecoxib, celecoxib, diclofenac, and indomethacin, but not meloxicam, etodolac, piroxicam, sulindac, ibuprofen, naproxen, and ketorolac. Interactions were found between NSAID use and exposure to renin-angiotensin blockers and contrast media.
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.
NSAIDs may also interact with certain herbal preparations sold as dietary supplements. Among the herbs known to interact with NSAIDs are bearberry ( Arctostaphylos uva-ursi ), feverfew ( Tanacetum parthenium ), evening primrose ( Oenothera biennis ), and gossypol, a pigment obtained from cottonseed oil and used as a male contraceptive. In most cases, the herb increases the tendency of NSAIDs to irritate the digestive tract. It is just as important for doctors to know which herbal remedies the patient is taking on a regular basis as it is for doctors to know the other prescription medications which are being taken.