DextromethorphanDextrorphanAntitussive AgentsLevorphanolCytochrome P-450 CYP2D6Oxidoreductases, O-DemethylatingQuinidineGuaifenesinChlorpheniramineCodeinePerhexilineCytochrome P-450 Enzyme SystemDebrisoquinGastric DilatationMorphinansExcitatory Amino Acid AntagonistsPseudobulbar PalsyReceptors, sigmaExpectorantsMemantineMicrosomes, LiverCoughReceptors, N-Methyl-D-AspartateDealkylation