Systematic (IUPAC) name
Clinical data
Legal status
  • Non-regulated
CAS number
ATC code None
Chemical data
Formula C23H35NO2 
Mol. mass 357.530 g/mol

Tonazocine (WIN-42,156) is an opioid analgesic of the benzomorphan family which made it to phase II clinical trials for the treatment of postoperative pain,[1] but development was apparently ceased and ultimately it was never marketed. Tonazocine is a partial agonist at both the mu-opioid and delta-opioid receptors, but acting more like an antagonist at the former and more like an agonist at the latter.[2][3] It lacks most of the side effects of other opioids such as adverse effects on the cardiovascular system and respiratory depression, but it can cause sedation (although to a lesser degree of typical opioids), and in some patients it may induce hallucinations.[4]

See also


  1. ^ American Chemical Society. Division of Medicinal Chemistry (1990). Annual Reports in Medicinal Chemistry. Academic Press. p. 12.  
  2. ^ Ward SJ, Pierson AK, Michne WF (February 1985). "Pharmacological profiles of tonazocine (Win 42156) and zenazocine (Win 42964)". Neuropeptides 5 (4-6): 375–8.  
  3. ^ Hudzik TJ, Howell A, Payza K, Cross AJ (May 2000). "Antiparkinson potential of delta-opioid receptor agonists". European Journal of Pharmacology 396 (2-3): 101–7.  
  4. ^ Jeffrey K. Aronson (30 November 2009). Meyler's Side Effects of Analgesics and Anti-inflammatory Drugs. Elsevier. p. 154.