Acemetacin is a non-steroidal anti-inflammatory drug used for the treatment of osteoarthritis, rheumatoid arthritis, lower back pain, and relieving post-operative pain. It is manufactured by Merck KGaA under the tradename Emflex and is available in the UK as a prescription-only drug. Other brand names for acemetacin include Rheutrop (Austria), Acemetadoc, Acephlogont, Azeat, Rantudil (Germany, Hungary, Mexico, Portugal, Turkey), Gamespir (Greece), Oldan, Reudol (Spain), Tilur (Switzerland), Ost-map (Egypt). Acemetacin is a glycolic acid ester of indomethacin. The pharmacological activity resulting from acemetacin administration in man is derived from the presence of both acemetacin and indomethacin. The precise pharmacological mode of action of acemetacin is not known. However, unlike other NSAIDs, acemetacin is only a relatively weak inhibitor of prostaglandin synthetase. Prostaglandins are known to have an antisecretory and cytoprotective effect on the gastric mucosa. Acemetacin shows activity in many of the established in vitro tests of anti-inflammatory activity including inhibition of the release of a number of mediators of inflammation. Acemetacin is well absorbed after oral administration. Its major metabolite is indomethacin, which, after repeated administration is present at levels in excess of those of acemetacin. Acemetacin is bound to plasma protein to a slightly lesser extent than indomethacin and has a relatively short plasma elimination half-life. It is eliminated by both hepatic and renal mechanisms. The pharmacokinetics appear to be linear at recommended therapeutic doses, unaffected by moderate renal or hepatic impairment, and unchanged in the elderly.