Specific Effects of Escitalopram on Neuroendocrine Response

• Status: Completed
• Trial end date: 2007-12-01
• Target enrollment: 0
• Participant gender: All

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.

• Accepts Healthy Volunteers?: Accepts Healthy Volunteers

Details

• Lead Sponsor: Queen's University
• Collaborator: H. Lundbeck A/S
• Treatments: Citalopram; Dexamethasone; Dexetimide

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.