Methorphan

{{Short description|Group of stereoisomers}}

{{Distinguish|racemorphan}}

{{Drugbox

| drug_name = Racemethorphan

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 462249979

| IUPAC_name = 3-Methoxy-17-methylmorphinan

| imageL = Levomethorphan.svg

| image_classL = skin-invert-image

| altL =

| imageR = Dextromethorphan.svg

| image_classR = skin-invert-image

| widthR =

| altR =

| captionLR = Levomethorphan (L), dextromethorphan (R)

| tradename =

| pregnancy_category =

| legal_status =

| legal_AU = S9

| legal_BR = A1

| legal_BR_comment = {{Cite web |author=Anvisa |author-link=Brazilian Health Regulatory Agency |date=2023-03-31 |title=RDC Nº 784 - Listas de Substâncias Entorpecentes, Psicotrópicas, Precursoras e Outras sob Controle Especial |trans-title=Collegiate Board Resolution No. 784 - Lists of Narcotic, Psychotropic, Precursor, and Other Substances under Special Control|url=https://www.in.gov.br/en/web/dou/-/resolucao-rdc-n-784-de-31-de-marco-de-2023-474904992 |url-status=live |archive-url=https://web.archive.org/web/20230803143925/https://www.in.gov.br/en/web/dou/-/resolucao-rdc-n-784-de-31-de-marco-de-2023-474904992 |archive-date=2023-08-03 |access-date=2023-08-16 |publisher=Diário Oficial da União |language=pt-BR |publication-date=2023-04-04}}

| legal_CA = Schedule I

| legal_DE = Anlage I

| legal_UK = Class A

| legal_UN = P I

| legal_US = Schedule II

| routes_of_administration =

| bioavailability =

| protein_bound =

| metabolism =

| elimination_half-life =

| excretion =

| ATC_prefix = None

| ATC_suffix =

| PubChem = 3008

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

| CAS_number = 510-53-2

| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}

| ChemSpiderID = 2901

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

| UNII = 8YB8F78WM1

| ChEBI = 146177

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

| ChEMBL = 22207

| C=18 | H=25 | N=1 | O=1

| molecular_weight =

| smiles = CN1CCC23CCCCC2C1CC4=C3C=C(C=C4)OC

| StdInChI_Ref = {{stdinchicite|changed|chemspider}}

| StdInChI = 1S/C18H25NO/c1-19-10-9-18-8-4-3-5-15(18)17(19)11-13-6-7-14(20-2)12-16(13)18/h6-7,12,15,17H,3-5,8-11H2,1-2H3

| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}

| StdInChIKey = MKXZASYAUGDDCJ-UHFFFAOYSA-N

}}

Methorphan comes in two isomeric forms, each with differing pharmacology and effects:

• Dextromethorphan{{snd}} An over-the-counter cough suppressant, as well as dissociative hallucinogen.
• Levomethorphan{{snd}} A potent opioid analgesic that was never clinically developed; a prodrug of the powerful opioid agonist analgesic levorphanol (Levo-Dromoran).

Racemethorphan is the racemic mixture of both of these stereoisomers.{{cite journal | vauthors = Aumatell A, Wells RJ | title = Chiral differentiation of the optical isomers of racemethorphan and racemorphan in urine by capillary zone electrophoresis | journal = Journal of Chromatographic Science | volume = 31 | issue = 12 | pages = 502–8 | date = December 1993 | pmid = 8120122 | doi = 10.1093/chromsci/31.12.502 }} It is listed under the Single Convention on Narcotic Drugs 1961 and is therefore listed in the United States as a Controlled Substance, specifically as a Narcotic in Schedule II with an ACSCN of 9732 and an annual aggregate manufacturing quota of 3 grams in 2014.{{cite web|url=http://www.deadiversion.usdoj.gov/quotas/conv_factor/index.html|title=Conversion Factors for Controlled Substances|website=www.deadiversion.usdoj.gov}}{{cite book | vauthors = Nordegren T | chapter = Racemethorphan | chapter-url = https://books.google.com/books?id=4yaGePenGKgC&pg=PA549 |title=The A-Z Encyclopedia of Alcohol and Drug Abuse |date=2002 |publisher=Brown Walker Press |location=Parkland, Fla. |isbn=978-1-58112-404-0 |pages=548–549 }} The salts in use are the hydrobromide (free base conversion ratio 0.770) and the tartrate (0.644).