Debrisoquine and dextromethorphan phenotyping and antidepressant treatment.

The correlation between debrisoquine and dextromethorphan oxidation polymorphism was studied in 16 depressed in-patients. There was a close correlation between both phenotypes (r = 0.81 p less than 0.0017). During a treatment with amitriptyline during two weeks there was no significant modification of the dextromethorphan polymorphism. In the same way, the association of amitriptyline and toloxatone during two other weeks did not change this polymorphism in a significant way, even if there was a non significant shift towards higher values of the dextromethorphan metabolic ratio.