Relationship between mirtazapine dose, plasma concentration, response, and side effects in clinical practice.
OBJECTIVE
The aim of this study was to evaluate the benefit of mirtazapine plasma concentration monitoring in a typical clinical setting.


METHODS
The relationship between mirtazapine plasma concentration, dose, response, and side effects was studied in 65 inpatients presenting with a depressive episode according to ICD-10. Plasma concentrations, the 17-item Hamilton Depression Rating (HAMD), and the UKU side effect rating were performed weekly. A subgroup of 45 patients was evaluated for a concentration-response relationship.


RESULTS
We found a low positive correlation between plasma concentration and dose. A low negative correlation between plasma concentration and increased duration of sleep was noted in the first week of mirtazapine treatment, but not during the entire observation time. Responders to mirtazapine treatment presented with higher plasma concentrations than non-responders, revealing a threshold concentration of 30 ng/mL.


CONCLUSIONS
The mirtazapine dose is a weak predictor of mirtazapine plasma concentrations. Plasma concentration measurements may therefore be useful to adjust mirtazapine doses in non-responders with plasma concentrations below 30 ng/mL. Sedative effects appear temporary and require no plasma concentration control when standard doses are administered.
Grasmäder
K
K
Department of Psychiatry, University of Bonn, Germany. kgrasmae@uni-bonn.de
Verwohlt
P L
PL
Kühn
K-U
KU
Frahnert
C
C
Hiemke
C
C
Dragicevic
A
A
von Widdern
O
O
Zobel
A
A
Maier
W
W
Rao
M L
ML
D000328:Adult; D000929:Antidepressive Agents, Tricyclic / Q000009:adverse effects / Q000097:blood / Q000627:therapeutic use; D016009:Chi-Square Distribution; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003866:Depressive Disorder / Q000097:blood* / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004563:Electrochemistry; D005260:Female; D006801:Humans; D008297:Male; D008803:Mianserin / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use; D008875:Middle Aged; D000078785:Mirtazapine; D011569:Psychiatric Status Rating Scales; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome
D000929:Antidepressive Agents, Tricyclic; D008803:Mianserin; D000078785:Mirtazapine