 Zomepirac provided analgesia comparable with usual intramuscular doses of morphine in postoperative pain and that with long-term use, neither tolerance to its analgesic effect nor psychological or physical dependence had been demonstrated.Zomepirac is the sodium salt of 5-(4-chlorobenzoyl)-1,4 dimethyl-1"H"-pyrrole-2-acetate dihydrate.It is a pyrrole-acetic acid which is structurally related to tolmetin.