3-Methoxymorphinan is an inactive metabolite of both dextromethorphan and levomethorphan, and has been shown to produce local anesthetic effects.[1] It is the CYP3A4 metabolite of the aforementioned drugs,[2] and is itself metabolized by the liver enzyme CYP2D6.[3]
^Hou CH, Tzeng JI, Chen YW, Lin CN, Lin MT, Tu CH, Wang JJ (August 2006). "Dextromethorphan, 3-methoxymorphinan, and dextrorphan have local anaesthetic effect on sciatic nerve blockade in rats". European Journal of Pharmacology. 544 (1–3): 10–16. doi:10.1016/j.ejphar.2006.06.013. PMID16844109.
^Min DI, Ku YM, Vichiendilokkul A, Fleckenstein LL (June 1999). "A urine metabolic ratio of dextromethorphan and 3-methoxymorphinan as a probe for CYP3A activity and prediction of cyclosporine clearance in healthy volunteers". Pharmacotherapy. 19 (6): 753–759. doi:10.1592/phco.19.9.753.31536. PMID10391422. S2CID32243163.
^Strauch K, Lutz U, Bittner N, Lutz WK (August 2009). "Dose-response relationship for the pharmacokinetic interaction of grapefruit juice with dextromethorphan investigated by human urinary metabolite profiles". Food and Chemical Toxicology. 47 (8): 1928–1935. doi:10.1016/j.fct.2009.05.004. PMID19445995.