Specific Effects of Escitalopram on Neuroendocrine Response
Information source: Queen's University
Information obtained from ClinicalTrials.gov on November 03, 2008
Link to the current ClinicalTrials.gov record.
Condition(s) targeted: Healthy
Intervention: Citalopram (Drug); Escitalopram (Drug); Dexamethasone (Drug); Cold Pressor Test (Behavioral)
Phase: N/A
Status: Recruiting
Sponsored by: Queen's University Official(s) and/or principal investigator(s):
Nicholas J Delva, MD, Principal Investigator, Affiliation: Queen's University
Overall contact:
Emily R Hawken, MSc, Phone: 613.548.5567, Ext: 5709, Email: ehawken@yahoo.com
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
antianxiolytic 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.
Clinical Details
Official title: Specific Effects of Escitalopram on Neuroendocrine Response
Study design: Randomized, Single Blind, Placebo Control, Crossover Assignment, Pharmacodynamics Study
Primary outcome: The effect of the drugs on serum cortisol and ACTH following a single dose of each drug.
Secondary outcome: Side effects following a single dose of the drug
Eligibility
Minimum age: 18 Years.
Maximum age: 59 Years.
Gender(s): Both.
Criteria:
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.
Locations and Contacts
Emily R Hawken, MSc, Phone: 613.548.5567, Ext: 5709, Email: ehawken@yahoo.com
Providence Continuing Care Centre, Mental Health Services, Kingston, Ontario K7L 4X3, Canada; Recruiting
Nicholas J Delva, MD, Phone: 613.548.5567, Ext: 5643, Email: delvan@pccchealth.org
Nicholas J Delva, MD, Principal Investigator
Additional Information
Starting date: September 2005
Ending date: December 2006
Last updated: July 18, 2006
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