Acemetacin (TVX 1322) is a carboxymethyl ester of indometacin. It is a potent non-steroidal anti-inflammatory drug, derived from the indol-3-acetic acid, whose activity is thought to be mainly through its active metabolite indomethacin. In clinical trials, acemetacin exhibits a better gastric tolerability compared to its active metabolite indometacin.

In rats pre-treated with COX-2 and NOS inhibitors, despite significant inhibition of COX activity, Acemetacin significantly reduces gastrointestinal damage compared to Indomethacin.

Acemetacin exerts its anti-inflammatory effect by inhibiting the synthesis of prostaglandins (PG). In inflamed synovial tissue, Acemetacin (10 μM) prevents the release of Prostaglandin E2 (PGE2). It inhibits the release of prostaglandin E2 in joint synovial tissues in vitro. During the incubation of gastric mucosa, the concentration-dependent inhibition of PGE accumulation by Acemetacin is not as effective as Indomethacin, and its reduction effect on gastric 6-keto-PGF1α and thromboxane B2 is also lower than that of Indomethacin.