Debrisoquine oxidative phenotyping and psychiatric drug treatment.

The debrisoquine/sparteine phenotype was determined in 51 patients with depression, who were subdivided into 3 groups in terms of their drug treatment. Log (MR) for each group was compared. Patients treated with benzodiazepines had the same distribution of log (MR) as the healthy population, but the distribution was shifted towards higher values in patients treated with neuroleptics and antidepressants. It appears that the phenotypic expression of debrisoquine oxidation may be modified by drugs whose metabolism follows the same route as debrisoquine. The debrisoquine test must be carefully interpreted in patients receiving several drugs in the same time.