chlormezanone

{{Short description|Withdrawn anxiolytic and muscle relaxant}}

{{Redirect|Trancopal|Trancopal Dolo|Flupirtine}}

{{Drugbox

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 460031099

| IUPAC_name = 2-(4-chlorophenyl)-3-methyl-1,1-dioxo-1,3-thiazinan-4-one

| image = Chlormezanone.svg

| alt = Skeletal formula of chlormezanone

| width = 210

| image2 = Chlormezanone-3D-spacefill.png

| alt2 = Space-filling model of the chlormezanone molecule

| width2 = 170

| tradename =

| Drugs.com = {{drugs.com|international|chlormezanone}}

| pregnancy_category =

| legal_status = Rx-only

| routes_of_administration = Oral

| bioavailability =

| metabolism =

| elimination_half-life = 40.5 hours

| excretion =

| IUPHAR_ligand = 7323

| CAS_number_Ref = {{cascite|correct|??}}

| CAS_number = 80-77-3

| ATC_prefix = M03

| ATC_suffix = BB02

| PubChem = 2717

| DrugBank_Ref = {{drugbankcite|correct|drugbank}}

| DrugBank = DB01178

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID = 2616

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = GP568V9G19

| KEGG_Ref = {{keggcite|correct|kegg}}

| KEGG = D00268

| ChEBI_Ref = {{ebicite|correct|EBI}}

| ChEBI = 3619

| ChEMBL_Ref = {{ebicite|changed|EBI}}

| ChEMBL = 1200714

| C=11 | H=12 | Cl=1 | N=1 | O=3 | S=1

| smiles = O=S1(CCC(N(C)C1C2=CC=C(C=C2)Cl)=O)=O

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChI = 1S/C11H12ClNO3S/c1-13-10(14)6-7-17(15,16)11(13)8-2-4-9(12)5-3-8/h2-5,11H,6-7H2,1H3

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey = WEQAYVWKMWHEJO-UHFFFAOYSA-N

}}

Chlormezanone (marketed under the brandname Trancopal or Fenaprim) is a drug used as an anxiolytic and a muscle relaxant.{{cite book | vauthors = Turner P, Volan G, Wiseman H |title=Drugs Handbook |date=1997 |publisher=Palgrave Macmillan |location=UK |isbn=978-1-349-13937-8 | url = https://books.google.com/books?id=0_OxCwAAQBAJ&dq=Chlormezanone+anxiolytic&pg=PA20 | page = 20 }}

Its use was discontinued in many countries in 1996 due to rare but serious cases of toxic epidermal necrolysis.{{cite journal | vauthors = Lerch M, Mainetti C, Terziroli Beretta-Piccoli B, Harr T | title = Current Perspectives on Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis | journal = Clinical Reviews in Allergy & Immunology | volume = 54 | issue = 1 | pages = 147–176 | date = February 2018 | pmid = 29188475 | doi = 10.1007/s12016-017-8654-z | s2cid = 46796285 }}