Healthy
Conditions
Keywords
antidepressive agents
Brief summary
Citalopram, a selective serotonin reuptake inhibitor (SSRI), is used as a neuroendocrine probe in human subjects to assess serotonin (5-hydroxytryptamine; 5-HT) function as reflected in prolactin and plasma cortisol release. Citalopram is a racemic mixture of equal parts of the S(+) and R(-) enantiomers. The S(+) form (escitalopram) has been identified as being the active isomer and inhibitor of serotonin reuptake and consequently antidepressant activity is associated almost exclusively with the S-enantiomer. Escitalopram has been shown to be approximately twice as potent as citalopram at the primary, high-affinity binding site on the human serotonin transporter. Interestingly, investigations have suggested an antagonistic interaction of the R- and S-enantiomer at an allosteric binding site on the serotonin transporter. This antagonism has been shown in animal studies where the addition of R-citalopram to escitalopram treatments significantly counteracts the antidepressant and anti-anxiolytic effects of escitalopram. From these clinical and experimental data, the researchers can anticipate that escitalopram would increase cortisol and prolactin in the neuroendocrine challenge paradigm more effectively than citalopram.
Detailed description
See above.
Interventions
DRUGCitalopram
40 mg, pill, single dose
DRUGEscitalopram
20 mg, pill, single dose
DRUGDexamethasone
1 mg, pill, single dose
BEHAVIORALCold Pressor Test
single test
Sponsors
H. Lundbeck A/S
Queen's University
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to 59 Years
Healthy volunteers
Yes
Inclusion criteria
* The age range will be restricted to between 18 and 59 years of age. * Subjects must be fit and have no history of significant illness. * Subjects must have no risk factors for HIV or viral hepatitis. * Subjects must be non-smokers, free of medication, and consume alcoholic and caffeinated beverages in moderation. * Subjects must also be in good psychological health with no history of psychiatric illness.
Exclusion criteria
* Personal history of psychiatric illness, habitual smoking, illicit or prescription drug use, high intake of alcohol (\>10 drinks/week) or caffeine (\>500 mg caffeine/day), shift work, pregnancy, personal or familial history of seizures, significant medical illness or treatment in the last six months, significant physical or laboratory abnormalities, or current use of a weight loss diet. * Women entering the study must be on a reliable form of birth control, i.e., tubal ligation, hysterectomy, oral contraceptives, abstinence, or vasectomy in partner.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| The effect of the drugs on serum cortisol and ACTH following a single dose of each drug. | 4hrs |
Secondary
| Measure | Time frame |
|---|---|
| Side effects following a single dose of the drug | 4hrs |
Countries
Canada
Outcome results
None listed