Table 1. Comparative Characteristics of Soluble and Immobilized Barley Oxalate Oxidase

1750 CUNICAL CHEMISTRY, Vol. 39, No. 8, 1993 pam, oxazepam, triazolam) or the antidepressants amitriptyline, clomipramine, demethyl domipramine, desipramine, imipramine, fluvoxamine, trimipramine; nortriptyline, however, interferes with norfluoxetine. Blood samples from patients treated with a combination of fluoxetine and benzodiazepines (bromazepam, alprazolam, temazepam, clorazepate dipotassium, oxazepam) were also tested and showedno interferences. For nine patients whose daily dose of fluoxetine or norfluoxetine was between 20 and 40 mg, blood concentrationsobtained were 24 to 420 ugfL and 52 to 419 igfL, respectively. These ranges are similar to those obtained in previous studies (5,10). Our results clearly show that (a) a blood concentrationof 10 gIL for fluoxetine or norfluoxetine can be detected by the described method, and (b) relevant interferences noted in other studies, especially benzodiazepines and imipramine, are not a problem in this method.