Difenax Mechanism of Action

Pharmacology: Pharmacodynamics: In rheumatic diseases, the anti-inflammatory and analgesic properties of diclofenac elicit a clinical response characterized by marked relief from signs and symptoms such as pain at rest, pain on movement, morning stiffness, and swelling of the joints, as well as by an improvement in function. In post-traumatic and post-operative inflammatory conditions, diclofenac rapidly relieves both spontaneous pain and pain on movement and reduces inflammatory, swelling and wound edema. In clinical trials diclofenac has also been found to exert a pronounced analgesic effect in moderate and severe pain of non-rheumatic origin.
Clinical studies have also revealed that, in primary dysmenorrhea, diclofenac is capable of relieving the pain and reducing the extent of bleeding.
Pharmacokinetics: Diclofenac is rapidly absorbed when given as an oral solution, rectal suppository, or by intramuscular injection. It is absorbed more slowly when given as enteric-coated tablet, especially when this dosage form is given with food. Although orally-administered diclofenac is almost completely absorbed, it is subjected to first-pass metabolism so that about 50% of the drug reaches the systemic circulation in the unchanged form. Diclofenac is also absorbed percutaneously, at therapeutic concentrations it is more than 99% bound to plasma proteins. Diclofenac penetrates synovial fluid where concentrations may persist even when plasma concentrations fall; diclofenac has been detected in breast milk. The terminal plasma half-life is about 1 to 2 hours. Diclofenac is metabolized to 4-hydroxydiclofenac, 5-hydroxydiclofenac, 3-hydroxydiclofenac and 4,5-dihydroxydiclofenac. It is then excreted in the form of glucuronide and sulphate conjugates mainly in the urine (about 60%) but also in the bile (about 35%) less than 1% is excreted as unchanged diclofenac.