Specific Effects of Escitalopram on Neuroendocrine Response

February 4, 2009 updated by: Queen's University

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.

Study Overview

Status

Completed

Conditions

Healthy

Intervention / Treatment

Detailed Description

See above.

Study Type

Observational

Enrollment (Actual)

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

Canada
- Ontario
  - Kingston, Ontario, Canada, K7L 4X3
    - Providence Centre, Mental Health Services

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 59 years (Adult)

Accepts Healthy Volunteers

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Normal healthy people

Description

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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Observational Models: Cohort
Time Perspectives: Prospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
The effect of the drugs on serum cortisol and ACTH following a single dose of each drug. Time Frame: 4hrs	4hrs

Secondary Outcome Measures

Outcome Measure	Time Frame
Side effects following a single dose of the drug Time Frame: 4hrs	4hrs

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Queen's University

Collaborators

H. Lundbeck A/S

Investigators

Principal Investigator: Nicholas J Delva, MD, Queen's University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

September 1, 2005

Primary Completion (Actual)

December 1, 2006

Study Completion (Actual)

December 1, 2007

Study Registration Dates

First Submitted

September 6, 2005

First Submitted That Met QC Criteria