Phenazocine (brand names Prinadol, Narphen) is an opioid analgesicdrug, which is related to pentazocine and has a similar profile of effects.[2]
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.[3]
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.[4] 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.[5]
Phenazocine was invented in the 1950s.[8][9] 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 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.[10]
Phenazocine was briefly used in the United States but fell out of favor;[citation needed] it remains a Schedule II substance under the Comprehensive Drug Abuse Control & Prevention Act (Controlled Substances Act) of 1970 (CSA) but is not manufactured. The DEA ACSCN for phenazocine is 9715 and its 2013 annual manufacturing quota was 6 grams.[11]
See also
Tapentadol - An opioid analgesic with reduced abuse-liability
^Harris LS, Pierson AK (February 1964). "Some Narcotic Antagonists in the Benzomorphan Series". Journal of Pharmacology and Experimental Therapeutics. 143: 141–8. PMID14163985.