Occupancy of serotonin transporters by paroxetine and citalopram during treatment of depression: a [(11)C]DASB PET imaging study.
Am J Psychiatry
; 158(11): 1843-9, 2001 Nov.
Article
em En
| MEDLINE
| ID: mdl-11691690
ABSTRACT
OBJECTIVE:
Selective serotonin reuptake inhibitors are commonly used to treat major depression; however, the percentage of serotonin (5-HT) transporter (5-HTT) sites occupied during clinical dosing is unknown. This study measured the proportion of 5-HTT sites blocked during paroxetine and citalopram treatment of depression and assessed the relationship between serum paroxetine levels and the proportion of 5-HTT sites blocked.METHOD:
Twelve medication-free depressed patients completed a 6-week trial of either paroxetine (N=8) or citalopram (N=4). Striatal 5-HTT binding potential was measured with [(11)C]DASB and positron emission tomography, before and after 4 weeks of treatment. The binding potential is proportional to receptor density. Striatal 5-HTT binding potential was measured twice in six healthy subjects and once in 11 healthy subjects.RESULTS:
A significant decrease in striatal 5-HTT binding potential was found after either treatment, compared to changes found over a 4-week period in healthy subjects. For patients treated with 20 mg/day of paroxetine (N=7), the mean proportion of 5-HTT sites occupied was 83%. For patients treated with 20 mg/day of citalopram (N=4), the mean 5-HTT occupancy was 77%. 5-HTT occupancy increased in a nonlinear relationship with serum levels of paroxetine such that a plateau of occupancy around 85% occurred for serum paroxetine levels greater than 28 microg/liter.CONCLUSIONS:
During treatment with clinical doses of paroxetine or citalopram, approximately 80% of 5-HTT receptors are occupied. This change in 5-HTT binding potential is greater than the known physiological range of changes in 5-HTT binding potential but may be necessary for some therapeutic effects.
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Base de dados:
MEDLINE
Assunto principal:
Encéfalo
/
Citalopram
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Tomografia Computadorizada de Emissão
/
Inibidores Seletivos de Recaptação de Serotonina
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Paroxetina
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Transtorno Depressivo Maior
Idioma:
En
Ano de publicação:
2001
Tipo de documento:
Article