3-Methoxymorphinan is an inactive metabolite of both dextromethorphan and levomethorphan, and has been shown to produce local anesthetic effects. It is the CYP3A4 metabolite of the aforementioned drugs, and is itself metabolized by the liver enzyme CYP2D6.
↑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.