Clinical data
ATC code
  • None
Legal status
Legal status
  • In general: non-regulated
  • 1-[(2S,6R,11S)-8-hydroxy-3,6,11-trimethyl-1,2,3,4,5,6-hexahydro-2,6-methano-3-benzazocin-11-yl]octan-3-one
CAS Number
PubChem CID
Chemical and physical data
Molar mass357.538 g·mol−1
3D model (JSmol)
  • O=C(CCCCC)CC[C@@]3([C@H]2N(CC[C@@]3(c1c(ccc(O)c1)C2)C)C)C
  • InChI=1S/C23H35NO2/c1-5-6-7-8-18(25)11-12-23(3)21-15-17-9-10-19(26)16-20(17)22(23,2)13-14-24(21)4/h9-10,16,21,26H,5-8,11-15H2,1-4H3/t21-,22+,23+/m0/s1

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 (probably via binding to and activating the κ-opioid receptor).[4]

See also


  1. ^ American Chemical Society. Division of Medicinal Chemistry (1990). Annual Reports in Medicinal Chemistry. Academic Press. p. 12. ISBN 978-0-12-040525-1. Retrieved 30 November 2011.
  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. doi:10.1016/0143-4179(85)90032-0. PMID 2860595. S2CID 20674308.
  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. doi:10.1016/S0014-2999(00)00209-0. PMID 10822062.
  4. ^ Aronson, Jeffrey K. (30 November 2009). Meyler's Side Effects of Analgesics and Anti-inflammatory Drugs. Elsevier. p. 154. ISBN 978-0-444-53273-2. Retrieved 30 November 2011.