zomepirac zomepirac zomepirac is an orally effective nonsteroidal anti-inflammatory drug (nsaid) that has antipyretic actions. it was developed by mcneil pharmaceutical, approved by the fda in 1980, and sold as the sodium salt zomepirac sodium, under the brand name zomax. due to its clinical effectiveness, it was preferred by doctors in many situations and obtained a large share of the analgesics market; however, it was subsequently withdrawn in march 1983 due to its tendency to cause serious anaphylaxis in a small, but unpredictable, subset of the patient population. zomepiracclinical dataroutes ofadministrationby mouthatc codem01ab04 (who) legal statuslegal status withdrawn identifiers iupac name 2-acetic acid cas number33369-31-2 npubchem cid5733drugbankdb04828 ychemspider5531 yunii822g987u9jchebichebi:35859 ychemblchembl19490 ycomptox dashboard (epa)dtxsid9023754 echa infocard100.046.780 chemical and physical dataformulac15h14clno3molar mass291.73 g·mol−13d model (jsmol)interactive image smiles o=c(c1c(cc(n1c)cc(=o)o)c)c2ccc(cl)cc2 inchi inchi=1s/c15h14clno3/c1-9-7-12(8-13(18)19)17(2)14(9)15(20)10-3-5-11(16)6-4-10/h3-7h,8h2,1-2h3,(h,18,19) ykey:zxvnmywkkdorea-uhfffaoysa-n y ny (what is this?) (verify) indications zomepirac was indicated for the management of mild to severe pain. multiple clinical trials demonstrated zomepirac to be more effective than aspirin or codeine alone and to be as effective as analgesic combinations containing codeine or other opioids. 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. chemical structure zomepirac is the sodium salt of 5-(4-chlorobenzoyl)-1,4 dimethyl-1h-pyrrole-2-acetate dihydrate. it is a pyrrole-acetic acid which is structurally related to tolmetin. the chemical structure differs from other nsaids in that the central benzene ring has been replaced by a pyrrole. mechanism of action zomepirac is a prostaglandin synthetase inhibitor. anaphylaxis zomepirac does not cause anaphylaxis directly, but it is metabolized by udp-glucuronosyltransferase (ugt) to a reactive glucuronide which binds irreversibly to plasma albumin. synthesis zomepirac can be synthesized from diethyl 1,3-acetonedicarboxylate, chloroacetone, and aqueous methylamine (menh2) via modification of the hantzsch pyrrole synthesis to give intermediate 1. saponification, monoesterification, and thermal decarboxylation gives ester 2. this is acylated with n,n-dimethyl-p-chlorobenzamide, and finally saponification gives zomepirac (3). zomepirac synthesis: