Phenazocine

{{Short description|Opioid analgesic}}

{{Drugbox

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 464200012

| IUPAC_name = (2R,6R,11R)-6,11-Dimethyl-3-(2-phenylethyl)-1,2,3,4,5,6-hexahydro-2,6-methano-3-benzazocin-8-ol

| image = Phenazocine2DCSD.svg

| image_class = skin-invert-image

| width = 220px

| image2 = Phenazocine 3D BS.png

| image_class2 = bg-transparent

| width2 = 220px

| tradename =

| pregnancy_AU =

| pregnancy_US =

| pregnancy_category =

| legal_AU = Schedule 9

| 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_UK = Class A

| legal_UK_comment = Withdrawn

| legal_US = Schedule II

| legal_DE = Anlage I

| routes_of_administration = Oral

| bioavailability =

| protein_bound =

| excretion =

| CAS_number_Ref = {{cascite|correct|CAS}}

| CAS_number = 58073-76-0

| ATC_prefix = N02

| ATC_suffix = AD02

| PubChem = 14707

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

| DrugBank =

| KEGG = C11790

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

| ChemSpiderID = 391631

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

| UNII = J0ND6N0AQC

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

| ChEMBL = 46399

| C=22 | H=27 | N=1 | O=1

| smiles = C[C@H]1[C@H]2Cc3ccc(cc3[C@@]1(CCN2CCc4ccccc4)C)O

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

| StdInChI = 1S/C22H27NO/c1-16-21-14-18-8-9-19(24)15-20(18)22(16,2)11-13-23(21)12-10-17-6-4-3-5-7-17/h3-9,15-16,21,24H,10-14H2,1-2H3/t16-,21+,22+/m0/s1

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

| StdInChIKey = ZQHYKVKNPWDQSL-KNXBSLHKSA-N

| synonyms = Fenazocina, Phenazocinum, DEA No. 9715

}}

Phenazocine (brand names Prinadol, Narphen) is an opioid analgesic drug, which is related to pentazocine and has a similar profile of effects.{{cite patent | country = US | number = 2959594 | title = Iso-benzmorphan derivatives }}

Effects of phenazocine include analgesia and euphoria, also may include dysphoria and hallucinations at high doses, most likely due to action at κ-opioid and σ receptors.{{cite journal |vauthors=Harris LS, Pierson AK | title=Some Narcotic Antagonists in the Benzomorphan Series | journal=Journal of Pharmacology and Experimental Therapeutics |date=February 1964 | pages=141–8 | volume= 143| issue=2 | doi=10.1016/S0022-3565(25)26704-0 | pmid=14163985}}

Phenazocine appears to be a much stronger analgesic with fewer side effects than pentazocine, probably due to a more favorable μ/κ binding ratio. Phenazocine is a much more potent analgesic than pentazocine and other drugs in the benzomorphan series, most probably due to the presence of an N-phenethyl substitution, which is known to boost μ-opioid activity in many classes of opioid analgesics.{{cite journal |vauthors=Feinberg AP, Creese I, Snyder SH | title=The opiate receptor: a model explaining structure-activity relationships of opiate agonists and antagonists | journal=Proceedings of the National Academy of Sciences USA |date=November 1976 | pages=4215–9 | volume=73 | issue=11 | pmid=186791 | doi=10.1073/pnas.73.11.4215 | pmc= 431391| bibcode=1976PNAS...73.4215F | doi-access=free }} Also, it does not cause spasm of the sphincter of Oddi, making it more suitable than morphine for the treatment of biliary or pancreatic pain.{{cite journal | author=Hopton D. | title=Double-blind clinical trial of the analgesic effects of phenazocine hydrobromide (Narphen) compared with morphine sulphate in patients with acute abdominal pain | journal=Gut |date=January 1971 | pages=51–4 | volume=12 | issue= 1 | pmid=4929685 | doi=10.1136/gut.12.1.51 | pmc=1411461}}

Regarding the two enantiomers of phenazocine, (R)-phenazocine{{clarify|There are multiple stereocenters, so the two enantiomers cannot be distinguished as R and S|date=September 2022}} has twenty times the potency of morphine as an analgesic,{{cite journal | doi=10.1038/184451a0 | title=Identification of Phenazocine, a Potent New Analgesic | journal=Nature | date=August 1959 | volume=184 | issue=4684 | pages=451 | last1=Clarke | first1=E. G. C. | pmid=13810504 | bibcode=1959Natur.184..451C | s2cid=4190489 | doi-access=free }} while (S)-phenazocine has about four times the potency of morphine.Textbook of Pharmacology - Page 117{{full|date=September 2022}}