View source for Phenazocine

{{Drugbox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 464200012
| IUPAC_name = (2''R'',6''R'',11''R'')-6,11-Dimethyl-3-(2-phenylethyl)-1,2,3,4,5,6-hexahydro-2,6-methano-3-benzazocin-8-ol
| image = Phenazocine.png
| width = 180

<!--Clinical data-->
| tradename =  
| pregnancy_AU = <!-- A / B1 / B2 / B3 / C / D / X -->
| pregnancy_US = <!-- A / B / C / D / X -->
| pregnancy_category =  
| legal_AU = Schedule 9
| legal_CA =  
| legal_UK = Class A, Withdrawn
| legal_US = Schedule II
| legal_status =  
| routes_of_administration = Oral

<!--Pharmacokinetic data-->
| bioavailability =  
| protein_bound =  
| excretion =

<!--Identifiers-->
| CAS_number_Ref = {{cascite|changed|??}}
| CAS_number = 127-35-5
| ATC_prefix = N02
| ATC_suffix = AD02
| PubChem = 14707
| DrugBank_Ref = {{drugbankcite|correct|drugbank}}
| DrugBank =  
|  ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}
| ChemSpiderID = 391631
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = J0ND6N0AQC
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 46399

<!--Chemical data-->
| C=22 | H=27 | N=1 | O=1 
| molecular_weight = 321.45588 g/mol
|  smiles = C[C@H]1[C@H]2Cc3ccc(cc3[C@@]1(CCN2CCc4ccccc4)C)O
|  InChI = 1/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
|  InChIKey = ZQHYKVKNPWDQSL-KNXBSLHKBY
|  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
}}
__NOTOC__

{{SI}}

{{CMG}}

==Overview==
'''Phenazocine''' (brand names '''Prinadol''', '''Narphen''') is an [[opioid analgesic]] [[pharmaceutical drug|drug]], which is related to [[pentazocine]] and has a similar profile of effects.

Effects of phenazocine include analgesia and [[euphoria]], also may include [[dysphoria]] and [[hallucinations]] at high doses, most likely due to action at [[Kappa opioid receptor|κ-opioid]] and [[Sigma receptor|σ receptors]].<ref name="Harris">{{cite journal | author= 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=  | pmid=14163985}}</ref>

Phenazocine appears to be a much stronger analgesic with fewer side effects than pentazocine, probably due to a more favorable [[mu opioid receptor|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.<ref name="Feinberg">{{cite journal | author= 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}}</ref>

Consequently phenazocine is some 4x the potency of [[morphine]] as an analgesic. 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.<ref name="Hopton">
{{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}}</ref>

==History==
Phenazocine was invented in the 1950s.<ref name="Clarke">{{cite journal | author= Clarke EG | title=Identification of Phenazocine, a Potent New Analgesic | journal=Nature | date=August 8, 1959 | pages=451–451 | volume= 184 | issue= Suppl 7  | pmid=13810504 | doi= 10.1038/184451a0}}</ref><ref name="Eckenhoff">{{cite journal | author= Eckenhoff JE | title=Phenazocine, a new benzomorphan narcotic analgesic | journal=Anesthesiology | date=May–June 1959 | pages=355–8 | volume=20 | issue=3 | pmid=13650222 | doi= 10.1097/00000542-195905000-00016}}</ref>  It was one of a number of [[benzomorphan]] opioids (including [[pentazocine]], [[dezocine]], and [[cyclazocine]]) developed in the search for non-addictive strong analgesics.

Phenazocine was once widely used, and was mainly supplied as 5&nbsp;mg tablets of the [[hydrobromide]] salt for sublingual use (Narphen, Prinadol and other names), but its use was discontinued in the [[United Kingdom]] in 2001.<ref name="discontinueUK">{{cite web |date=February 2001 | url = http://www.connectingforhealth.nhs.uk/systemsandservices/data/readcodes/docs/tandc0201.pdf | title = Monthly Release Terming and Coding Newsletter | format = PDF | publisher = NHS Information Authority | accessdate = 2008-01-11}} {{Dead link|date=October 2010|bot=H3llBot}}</ref>

Phenazocine was briefly used in the United States but fell out of favour for the above-mentioned reasons;{{which|date=May 2013}}{{Citation needed|date=May 2013}} it remains a Schedule II substance under the Comprehensive Drug Abuse Control & Prevention Act (aka Controlled Substances Act) of 1970 (CSA) but is not manufactured; other Schedule II narcotics not in use in the United States include [[bezitramide]] and [[metopon]].  The DEA ACSCN for phenazocine is 9715 and its 2013 annual manufacturing quota was 6 grammes <ref>http://www.deadiversion.usdoj.gov/fed_regs/quotas/2013/fr0620.htm</ref>

==References==
{{Reflist|2}}

{{Analgesics}}
{{Hallucinogens}}
{{Opioidergics}}

[[Category:Benzomorphans]]
[[Category:Kappa agonists]]
[[Category:Mu-opioid agonists]]
[[Category:Phenols]]
[[Category:Synthetic opioids]]
[[Category:Drug]]