Clinical data
Other namesDXO, Dextrorphanol
ATC code
  • None
Legal status
Legal status
  • US: Unscheduled[1]
  • (+)-17-methyl-9a,13a,14a-morphinan-3-ol
CAS Number
PubChem CID
CompTox Dashboard (EPA)
ECHA InfoCard100.004.323 Edit this at Wikidata
Chemical and physical data
Molar mass257.377 g·mol−1
3D model (JSmol)
  • CN1CC[C@@]23CCCC[C@@H]2[C@@H]1Cc4c3cc(O)cc4
  • InChI=1S/C17H23NO/c1-18-9-8-17-7-3-2-4-14(17)16(18)10-12-5-6-13(19)11-15(12)17/h5-6,11,14,16,19H,2-4,7-10H2,1H3/t14-,16+,17+/m1/s1 ☒N
 ☒NcheckY (what is this?)  (verify)

Dextrorphan (DXO) is a psychoactive drug of the morphinan class which acts as an antitussive or cough suppressant and dissociative hallucinogen. It is the dextrorotatory enantiomer of racemorphan; the levorotatory enantiomer is levorphanol. Dextrorphan is produced by O-demethylation of dextromethorphan by CYP2D6. Dextrorphan is an NMDA antagonist and contributes to the psychoactive effects of dextromethorphan.[2]



Site Ki (nM) Species Ref
486–906 Rat [4]
σ1 118–481 Rat [4]
σ2 11,325–15,582 Rat [4]
MORTooltip μ-Opioid receptor 420
DORTooltip δ-Opioid receptor 34,700 Rat [4]
KORTooltip κ-Opioid receptor 5,950 Rat [4]
SERTTooltip Serotonin transporter 401–484 Rat [4]
NETTooltip Norepinephrine transporter ≥340 Rat [4]
DATTooltip Dopamine transporter >1,000 Rat [4]
5-HT1A >1,000 Rat [4]
5-HT1B/1D 54% at 1 μM Rat [4]
5-HT2A >1,000 Rat [4]
α1 >1,000 Rat [4]
α2 >1,000 Rat [4]
β 35% at 1 μM Rat [4]
D2 >1,000 Rat [4]
H1 95% at 1 μM Rat [4]
mAChRsTooltip Muscarinic acetylcholine receptors 100% at 1 μM Rat [4]
nAChRsTooltip Nicotinic acetylcholine receptors 1,300–29,600
Rat [4]
VDSCsTooltip Voltage-dependent sodium channels ND ND ND
Values are Ki (nM), unless otherwise noted. The smaller the value, the more strongly the drug binds to the site.

The pharmacology of dextrorphan is similar to that of dextromethorphan (DXM). However, dextrorphan is much more potent as an NMDA receptor antagonist as well much less active as a serotonin reuptake inhibitor, but retains DXM's activity as a norepinephrine reuptake inhibitor.[8] It also has more affinity for the opioid receptors than dextromethorphan, significantly so at high doses.


Dextrorphan has a notably longer elimination half-life than its parent compound, and therefore has a tendency to accumulate in the blood after repeated administration of normally dosed dextromethorphan formulations.[citation needed] It is further converted to 3-HM by CYP3A4 or glucuronidated.[9]

Society and culture

Legal status

Dextrorphan was formerly a Schedule I controlled substance in the United States, but was unscheduled on October 1, 1976.[10]


Dextrorphan was under development for the treatment of stroke, and reached phase II clinical trials for this indication, but development was discontinued.[11]

Environmental presence

In 2021, dextrorphan was identified in >75% of sludge samples taken from 12 wastewater treatment plants in California. The same study associated dextrorphan with estrogenic activity by using predictive modelling, before observing it in in vitro. [12]

See also


  1. ^ Bensinger, Peter (October 1, 1976). "Dextrophan and Nalbuphine; Removal from Schedules" (PDF). NARA. Retrieved June 26, 2023.
  2. ^ Zawertailo LA, Kaplan HL, Busto UE, Tyndale RF, Sellers EM (August 1998). "Psychotropic effects of dextromethorphan are altered by the CYP2D6 polymorphism: a pilot study". Journal of Clinical Psychopharmacology. 18 (4): 332–337. doi:10.1097/00004714-199808000-00014. PMID 9690700.
  3. ^ Roth BL, Driscol J. "PDSP Ki Database". Psychoactive Drug Screening Program (PDSP). University of North Carolina at Chapel Hill and the United States National Institute of Mental Health. Retrieved 14 August 2017.
  4. ^ a b c d e f g h i j k l m n o p q r s t Nguyen L, Thomas KL, Lucke-Wold BP, Cavendish JZ, Crowe MS, Matsumoto RR (2016). "Dextromethorphan: An update on its utility for neurological and neuropsychiatric disorders". Pharmacol. Ther. 159: 1–22. doi:10.1016/j.pharmthera.2016.01.016. PMID 26826604.
  5. ^ Werling LL, Keller A, Frank JG, Nuwayhid SJ (2007). "A comparison of the binding profiles of dextromethorphan, memantine, fluoxetine and amitriptyline: treatment of involuntary emotional expression disorder". Exp. Neurol. 207 (2): 248–57. doi:10.1016/j.expneurol.2007.06.013. PMID 17689532. S2CID 38476281.
  6. ^ Taylor CP, Traynelis SF, Siffert J, Pope LE, Matsumoto RR (2016). "Pharmacology of dextromethorphan: Relevance to dextromethorphan/quinidine (Nuedexta®) clinical use". Pharmacol. Ther. 164: 170–82. doi:10.1016/j.pharmthera.2016.04.010. PMID 27139517.
  7. ^ Raynor K, Kong H, Mestek A, Bye LS, Tian M, Liu J, Yu L, Reisine T (1995). "Characterization of the cloned human mu opioid receptor". J. Pharmacol. Exp. Ther. 272 (1): 423–8. PMID 7815359.
  8. ^ Pechnick RN, Poland RE (May 2004). "Comparison of the effects of dextromethorphan, dextrorphan, and levorphanol on the hypothalamo-pituitary-adrenal axis". The Journal of Pharmacology and Experimental Therapeutics. 309 (2): 515–522. doi:10.1124/jpet.103.060038. PMID 14742749. S2CID 274504.
  9. ^ Yu A, Haining RL (November 2001). "Comparative contribution to dextromethorphan metabolism by cytochrome P450 isoforms in vitro: can dextromethorphan be used as a dual probe for both CTP2D6 and CYP3A activities?". Drug Metabolism and Disposition. 29 (11): 1514–20. PMID 11602530.
  10. ^ DEA. "Lists of: Scheduling Actions Controlled Substances Regulated Chemicals" (PDF). Archived from the original (PDF) on 2016-04-17. Retrieved 2010-09-24.
  11. ^ "Dextrorphan - AdisInsight".
  12. ^ Black GP, He G, Denison MS, Young TM (May 2021). "Using Estrogenic Activity and Nontargeted Chemical Analysis to Identify Contaminants in Sewage Sludge". Environmental Science & Technology. 55 (10): 6729–6739. Bibcode:2021EnST...55.6729B. doi:10.1021/acs.est.0c07846. PMC 8378343. PMID 33909413.