Single dose oral diclofenac for postoperative pain.

Diclofenac is a benzene-acetic acid derivative that acts, like other NSAIDs, by inhibiting cyclo-oxygenase isoforms that mediate the body's production of the prostaglandins implicated in pain and inflammation. Diclofenac is widely available as a sodium or potassium salt. Diclofenac potassium tablets are known as 'immediate-release' diclofenac as absorption takes place in the gastrointestinal tract whereas 'delayed-release' (enteric-coated) diclofenac tablets resist dissolution until reaching the duodenum. An existing review showed that diclofenac was an effective treatment for acute postoperative pain but did not address the distinction between potassium and sodium salts due to lack of data. The aim of this update is to gather and add appropriate information published subsequently and, data permitting, examine any potential differences between the two different diclofenac formulations.