The relationship of plasma clomipramine and N-desmethylclomipramine to response in obsessive-compulsive disorder.

The clinical significance of the effects of pharmacotherapy and the relationship between plasma tricyclic concentrations and outcome in 33 obsessive-compulsive disorder (OCD) patients who completed 10 weeks of treatment with clomipramine (239.4 +/- 57.0 mg/day) were analyzed. Results revealed that at the end of treatment, OCD symptoms had decreased to a subclinical level in 15 (47%) patients and that nearly 33 percent of the sample was virtually symptom free. However, 1 out of 4 patients failed to improve. Analysis of plasma levels (clomipramine 169.9 +/- 102.1 ng/ml; N-desmethylclomipramine 379.0 +/- 160.6 ng/ml) revealed that responders had significantly higher clomipramine levels and a trend toward lower desmethylclomipramine/clomipramine ratios. A significant degree of correlation was also obtained between plasma levels of clomipramine, but not N-desmethylclomipramine, and post-treatment outcome measures.