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.

Indometacin (INN and BAN) or indomethacin (AAN, USAN, and former BAN) is a nonsteroidal anti-inflammatory drug (NSAID) commonly used as a prescription medication to reduce fever, pain, stiffness, and swelling from inflammation. Indomethacin has analgesic, anti-inflammatory, and antipyretic properties. The mechanism of action of Indometacin, like that of other NSAIDs, is not completely understood but involves inhibition of cyclooxygenase (COX-1 and COX-2). Indomethacin is a potent inhibitor of prostaglandin synthesis in vitro. Indomethacin concentrations reached during therapy have produced in vivo effects. Prostaglandins sensitize afferent nerves and potentiate the action of bradykinin in inducing pain in animal models. Prostaglandins are mediators of inflammation. Because indomethacin is an inhibitor of prostaglandin synthesis, its mode of action may be due to a decrease of prostaglandins in peripheral tissues. Indometacin is indicated for: Moderate to severe rheumatoid arthritis including acute flares of chronic disease, Moderate to severe ankylosing spondylitis, Moderate to severe osteoarthritis, Acute painful shoulder (bursitis and/or tendinitis), Acute gouty arthritis. In general, adverse effects seen with indomethacin are similar to all other NSAIDs. For instance, indometacin inhibits both cyclooxygenase-1 and cyclooxygenase-2, it inhibits the production of prostaglandins in the stomach and intestines, which maintain the mucous lining of the gastrointestinal tract. Indometacin, therefore, like other non-selective COX inhibitors can cause peptic ulcers. These ulcers can result in serious bleeding and/or perforation requiring hospitalization of the patient. To reduce the possibility of peptic ulcers, indomethacin should be prescribed at the lowest dosage needed to achieve a therapeutic effect, usually between 50–200 mg/day. It should always be taken with food. Nearly all patients benefit from an ulcer protective drug (e.g. highly dosed antacids, ranitidine 150 mg at bedtime, or omeprazole 20 mg at bedtime). Other common gastrointestinal complaints, including dyspepsia, heartburn and mild diarrhea are less serious and rarely require discontinuation of indomethacin.