Paroxetine serum concentrations in depressed patients and response to treatment.
BACKGROUND
There is no established relationship between the serum concentration of selective serotonin reuptake inhibitors (SSRIs) and clinical response in depressed patients.


METHODS
We analyzed paroxetine concentrations in serum of 46 depressed patients during treatment with a fixed dosage of 40 mg paroxetine.


RESULTS
After 5 weeks 29 patients responded to treatment, while 17 did not. Analysis of variance with repeated measures (ANOVA-rm) revealed a significant effect of "response" with responders having lower serum concentrations throughout the treatment period, when compared to non-responders. After 2, 3, and 4 weeks of treatment, we could define an upper threshold of paroxetine serum concentrations (week 1 : 22.7 ng/mL; week 2 : 43 ng/mL; week 3 : 53.4 ng/mL; week 4 : 39.1 ng/mL) above which response to treatment was unlikely.


CONCLUSIONS
We conclude that -- in contrast to other pharmacological approaches -- high rather than low drug serum concentrations may be associated with non-response in paroxetine treatment of depressed patients.
Gilles
M
M
Central Institute of Mental Health, Mannheim, Germany.
Deuschle
M
M
Kellner
S
S
Shams
M
M
Krumm
B
B
Härtter
S
S
Heuser
I
I
Hiemke
C
C
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D018687:Antidepressive Agents, Second-Generation / Q000097:blood* / Q000627:therapeutic use*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003863:Depression / Q000097:blood* / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D004563:Electrochemistry / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017374:Paroxetine / Q000097:blood* / Q000627:therapeutic use*; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome
D018687:Antidepressive Agents, Second-Generation; D017374:Paroxetine