Dextromethorphan metabolism

Casner, P. (2005). The effect of CYP2D6 polymorphisms on dextromethorphan metabolism in Mexican Americans. /. Clin. Pharmacol., 45, 1230-5. 

Schmid B, Bircher J, Preisig R, et al. Polymorphic dextromethorphan metabolism co-segregation of oxidative O-demethylation with debrisoquine hydroxylation. Clin Pharmacol Ther 1985 38 618-624. 

It is also possible to determine a single time-point, dextromethorphan metabolic ratio in plasma within 2-5 hr after an oral dose or in a 6-hr saliva sample (229,230) however, neither of these alternative approaches has been widely used. 

Hou ZY, Pickle LW, Meyer PS, et al. Salivary analysis of determination of dextromethorphan metabolic phenotype. Clin Pharmacol Ther 1991 49 410419. 

Evans WE, Relling MV. Concordance of P450 2D6 (debrisoquine hydroxylase) phenotype and genotype inability of dextromethorphan metabolic ratio to discriminate reliably heterozygous and homozygous extensive metabolizers. Pharmacogenetics 1991 1 143-148. 

Funck-Brentano C, Thomas G, Jacqz-Algrain E, et al. Polymorphism of dextromethorphan metabolism relationships between phenotype, genotype and response to the administration of encainide in humans. J Pharmacol Exp Ther 1992 263 780-786. 

Irshaid YM, Al-Hadidi HF, Latif A, et al. Dextromethorphan metabolism in Jordanians dissociation of dextromethorphan O-demethylation from debrisoquine 4-hydroxylation. Eur J Clin Metab Pharmacokinet 1996 21 301-307. 

Witherow LE, Houston IB. 1999. Sigmoidal kinetics of CYP3A substrates an approach for scaling dextromethorphan metabolism in hepatic microsomes and isolated hepatocytes to predict in vivo clearance in rat. I Pharmacol Exp Ther 290 58-65. 

Hartter S, Dingemanse J, Baier D, Ziegler G, Hiemke C. Inhibition of dextromethorphan metabolism by moclobemide. Psychopharmacology (Berl) 1998 135(l) 22-6. 

Figure 1-3. Frequency distribution of dextromethorphan metabolic ratios (MRs) in Asians, African Americans, Caucasians, and Mexican Americans. The MR is the log10 of the ratio between urinary dextromethorphan and one of its main metabolites, dextrophan. Lower MRs indicate more active enzyme activities.

Bartoli A, Gatt G, Chimienti M, Corbellini D, Perrucca E. Does lidoeaine affect oxidative dextromethorphan metabolism in vivo" G ltd Chim Clin (1993/4) 18,125-9. 

Drug-drug interactions The inhibitory effect of bupropion on CYP2D6 metabolism has been previously demonstrated in vivo, for example by inhibition of dextromethorphan metabolism (SEDA-30, 20). An in vitro study using desipramine as substrate has suggested that this effect is due to the metabolites erythrohydrobupropion and threohydrobupropion, which were much more potent inhibitors of CYP2D6 than hydroxybupropion or bupropion itself [71 ]. 

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