Comparison of the effects of citalopram and escitalopram on 5-Ht-mediated neuroendocrine responses

Acute oral administration of selective serotonin re-uptake inhibitors (SSRIs) increases plasma cortisol by facilitating brain serotonin activity. Recently, salivary cortisol sampling has grown in popularity as a noninvasive means of assessing HPA axis activity. The aim of the present study was to find out whether acute oral administration of the SSRI, citalopram, increases salivary cortisol in healthy volunteers and whether the increase produced by an equivalent dose of its active isomer, escitalopram, is greater. A total of 15 healthy subjects were tested on three occasions receiving either oral citalopram ( 20 mg), escitalopram ( 10 mg), or placebo in a double-blind, randomized, crossover design. Salivary cortisol and plasma cortisol and prolactin were measured for 240 min after each treatment. Relative to placebo, both citalopram and escitalopram increased salivary and plasma cortisol levels with no evidence of consistent differences between them. Plasma prolactin concentration was not altered by either active treatment. Plasma and salivary cortisol responses after citalopram but not escitalopram correlated significantly. The present study does not support an enhanced effect of escitalopram on 5-HT-mediated neuroendocrine responses.