Clinical data
Other namesWIN-1783, BW 47-442
ATC code
  • None
Legal status
Legal status
  • (±)-6-(Dimethylamino)-5-methyl-4,4-diphenyl-3-hexanone
CAS Number
  • 466-40-0
    5341-49-1 (HCl)
    26594-41-2 ((R)-form)
    561-10-4 ((S)-form)
    7487-81-2 ((S)-form (HCl))
PubChem CID
Chemical and physical data
Molar mass309.453 g·mol−1
3D model (JSmol)
  • O=C(CC)C(C1=CC=CC=C1)(C(C)CN(C)C)C2=CC=CC=C2
  • InChI=1S/C21H27NO/c1-5-20(23)21(17(2)16-22(3)4,18-12-8-6-9-13-18)19-14-10-7-11-15-19/h6-15,17H,5,16H2,1-4H3

Isomethadone (INN, BAN; trade name Liden; also known as isoamidone) is a synthetic opioid analgesic and antitussive related to methadone that was used formerly as a pharmaceutical drug but is now no longer marketed.[2][3][4][5] Isomethadone was used as both an analgesic and antitussive. It binds to and activates both the μ- and δ-opioid receptors, with the (S)-isomer being the more potent of the two enantiomers.[6] Isomethadone is a Schedule II controlled substance in the United States, with an ACSCN of 9226 and a 2014 aggregate manufacturing quota of 5 g. The salts in use are the hydrobromide (HBr, free base conversion ratio 0.793), hydrochloride (HCl, 0.894), and HCl monohydrate (0.850).[7] Isomethadone is also regulated internationally as a Schedule I controlled substance under the United Nations Single Convention on Narcotic Drugs of 1961.[8]

See also


  1. ^ Anvisa (2023-03-31). "RDC Nº 784 - Listas de Substâncias Entorpecentes, Psicotrópicas, Precursoras e Outras sob Controle Especial" [Collegiate Board Resolution No. 784 - Lists of Narcotic, Psychotropic, Precursor, and Other Substances under Special Control] (in Brazilian Portuguese). Diário Oficial da União (published 2023-04-04). Archived from the original on 2023-08-03. Retrieved 2023-08-16.
  2. ^ Macdonald F (1997). Dictionary of Pharmacological Agents. CRC Press. p. 1169. ISBN 978-0-412-46630-4. Retrieved 16 May 2012.
  3. ^ Morton IK, Hall JM (1999). Concise Dictionary of Pharmacological Agents: Properties and Synonyms. Springer. p. 157. ISBN 978-0-7514-0499-9. Retrieved 16 May 2012.
  4. ^ Keats AS, Beecher HK (June 1952). "Analgesic potency and side action liability in man of heptazone, WIN 1161-2, 6-methyl dihydromorphine, Metopon, levo-isomethadone and pentobarbital sodium, as a further effort to refine methods of evaluation of analgesic drugs". The Journal of Pharmacology and Experimental Therapeutics. 105 (2): 109–29. PMID 14928215.
  5. ^ Winter CA, Flataker L (November 1952). "Antitussive action of d-isomethadone and d-methadone in dogs". Proceedings of the Society for Experimental Biology and Medicine. New York, N.Y.: Society for Experimental Biology and Medicine. 81 (2): 463–5. doi:10.3181/00379727-81-19912. PMID 13027341. S2CID 36487588.
  6. ^ Portoghese PS, Poupaert JH, Larson DL, et al. (June 1982). "Synthesis, X-ray crystallographic determination, and opioid activity of erythro-5-methylmethadone enantiomers. Evidence which suggests that mu and delta opioid receptors possess different stereochemical requirements". Journal of Medicinal Chemistry. 25 (6): 684–8. doi:10.1021/jm00348a015. PMID 6284938.
  7. ^ "Final Adjusted Aggregate Production Quotas for Schedule I and II Controlled Substances and Assessment of Annual Needs for the List I Chemicals Ephedrine, Pseudoephedrine, and Phenylpropanolamine for 2014". Code of Federal Regulations. Archived from the original on 2016-03-04. Retrieved 2016-02-28.
  8. ^ Nordegren T (1 March 2002). The A-Z Encyclopedia of Alcohol and Drug Abuse. Universal-Publishers. p. 366. ISBN 978-1-58112-404-0. Retrieved 16 May 2012.