ISSN:
1432-1041
Keywords:
Key words Concentration-effect relationship
;
Clomipramine
;
Naturalistic study
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Medicine
Notes:
Abstract Objectives: The aim of the present study was to characterise onset of response to clomipramine treatment in a naturalistic setting and to investigate the relationship between concentration and delayed response, postulated to reflect drug-specific response to antidepressant therapy. Methods: Ninety-eight depressed patients were prescribed clomipramine in an open flexible manner and followed for depressive symptoms (Montgomery-Åsberg depression scale) over a maximum 12 weeks follow-up period. All patients had at least one concentration measurement for therapeutic drug monitoring purpose. Results: Firstly, survival analysis revealed a probability of 15.4% for patients not to show 50% improvement over baseline by week 12, and thus to be considered as non-responders. Median time to onset of response was 31 days for responders, indicating a relatively high probability of delayed response under routine treatment. Secondly, pattern analysis indicated a significant association between early and abrupt response on the one hand and delayed and gradual response on the other. A tendency towards an association between delayed and persistent response was also observed. Finally, receiver operating characteristics analysis allowed identification of a highly significant lower threshold of 230 ng · ml−1 for the sum of clomipramine and desmethyl-clomipramine, as measured at week 3, with respect to response from week 3 onward. Predictive values were 68.8% and 81.0% for concentrations above and below this threshold to predict delayed response and non-response, respectively. Thresholds were 55 ng · ml−1 for parent compound and 180 ng · ml−1 for metabolite. Conclusion: This approach supports the hypothesis that delayed response may be concentration dependent and thus may reflect true drug effect. As a consequence, monitoring clomipramine concentration about 3 weeks after initiation of therapy may valuably contribute to help clinicians decide about the adequacy of ongoing therapy.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002280050572
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