Phenazocine (brand names Prinadol, Narphen) is an opioid analgesic drug, which is related to pentazocine and has a similar profile of effects.

[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.

[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.

[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.