Mephenesin

{{Short description|Muscle relaxer & antidote for strychnine poisoning}}

{{Drugbox

| Verifiedfields = changed

| verifiedrevid = 462248479

| IUPAC_name = 3-(2-methylphenoxy)propane-1,2-diol

| image = Mephenesin.svg

| image_class = skin-invert-image

| tradename =

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

| pregnancy_category =

| legal_status =

| routes_of_administration =

| bioavailability =

| metabolism =

| excretion =

| CAS_number_Ref = {{cascite|changed|??}}

| CAS_number = 59-47-2

| ATC_prefix = M03

| ATC_suffix = BX06

| PubChem = 4059

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

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

| ChemSpiderID = 3919

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

| UNII = 7B8PIR2954

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

| KEGG = D02595

| ChEMBL_Ref = {{ebicite|correct|EBI}}

| ChEMBL = 229128

| NIAID_ChemDB = 017830

| C=10 | H=14 | O=3

| smiles = O(c1ccccc1C)CC(O)CO

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

| StdInChI = 1S/C10H14O3/c1-8-4-2-3-5-10(8)13-7-9(12)6-11/h2-5,9,11-12H,6-7H2,1H3

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

| StdInChIKey = JWDYCNIAQWPBHD-UHFFFAOYSA-N

}}

Mephenesin (INN), also called myanesin,{{cite web |title=Mephenesin Definition & Meaning |url=https://www.merriam-webster.com/medical/mephenesin |website=Merriam-Webster Medical}}{{cite journal | vauthors = Berger FM | title = The mode of action of myanesin | journal = British Journal of Pharmacology and Chemotherapy | volume = 2 | issue = 4 | pages = 241–50 | date = December 1947 | pmid = 19108125 | pmc = 1509790 | doi = 10.1111/j.1476-5381.1947.tb00341.x }} is a centrally acting muscle relaxant. It can be used as an antidote for strychnine poisoning. Mephenesin however presents with the major drawbacks of having a short duration of action and a much greater effect on the spinal cord than the brain, resulting in pronounced respiratory depression at clinical doses and therefore a very low therapeutic index. It is especially dangerous and potentially fatal in combination with alcohol and other depressants.{{cite web|title=Mephenesin|url=https://www.mims.com/USA/drug/info/mephenesin/|publisher=MIMS}} Mephenesin was the inspiration for the synthesis of a derivative of 1,3-propanediol, meprobamate, by Bernard Ludwig and Frank Berger,{{cite journal | vauthors = Ban TA | title = The role of serendipity in drug discovery | journal = Dialogues in Clinical Neuroscience | volume = 8 | issue = 3 | pages = 335–44 | date = 2006 | pmid = 17117615 | pmc = 3181823 | doi = 10.31887/DCNS.2006.8.3/tban }} the first tranquilizer to see widespread clinical use. Mephenesin is no longer available in North America but is used in Italy and a few other countries.{{cite web|title=Mephenesin|url=https://www.drugs.com/international/mephenesin.html|publisher=Drugs.com}} Its use has largely been replaced by the related drug methocarbamol, which is better absorbed.{{cite journal|last=Huf|first=Ernst|title=Comparative Plasma Levels of Mephenesin, Mephenesin Carbamate and Methocarbamol|journal=Proceedings of the Society for Experimental Biology and Medicine|year=1959|volume=102|issue=2|pages=276–7|url=http://ebm.sagepub.com/content/102/2/276.abstract|publisher=Experimental Biology & Medicine|doi=10.3181/00379727-102-25218|pmid=14403806|s2cid=37483102|access-date=8 January 2014|display-authors=etal}}

Mephenesin may be an NMDA receptor antagonist.{{cite journal | vauthors = Keshavarz M, Showraki A, Emamghoreishi M | title = Anticonvulsant Effect of Guaifenesin against Pentylenetetrazol-Induced Seizure in Mice | journal = Iran J Med Sci | volume = 38 | issue = 2 | pages = 116–21 | year = 2013 | pmid = 23825891 | pmc = 3700057 }} Mephenesin was previously used in France as an OTC muscle relaxant called Décontractyl but was taken out of production by Sanofi Aventis and due to a French Health Ministry decree in July 2019.