It is the naproxen anion that circulates in the blood bound to plasma proteins known as albumins which are formed in the liver and create the osmotic pressure used to draw fluid into the capillaries. This inhibits inflammation but produces a side effect of prolonged clotting time and possible kidney problems and gastric bleeding. Approved by the Food and Drug Administration in 1994 for over the counter use it is now sold under its OTC name Aleve. Aleve is distributed by Procter and Gamble and is produced by Syntex Laboratories of Palo Alto, California in a tablet form with 200mg Naproxen and 20mg sodium. Side effects include digestive problems, kidney and liver damage when taken in overdose.
Naproxen works by inhibiting prostaglandin synthesis, specifically the cyclo-oxygenase enzyme.
Prostaglandins are a family of fatty acids that serve numerous autocrine regulatory functions including uterine contractions, gastric acid secretion, and the promotion of inflammation. Autocrine molecules are produced and act within the same tissue of an organ. There are two isoenzyme forms of cyclo-oxygenase. Isoenzymes are formed when slightly different models, differing by a few amino acids, of the same enzyme are produced by different organs. Inhibiting cox1 effects the synthesis of prostacyclin which protects the stomach lining which is why they are irritating to the stomach.