H. Chung,1 S. Yi,1 S. Moon,1 J. Park,1 S. Yoon,1 J. Cho,1 K. Yu,1 J. Chung2; 1Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Korea, Republic of, 2Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Bundang Hospital, Seongnam, Korea, Republic of

BACKGROUND: Escitalopram is a widely used selective serotonin reuptake inhibitor for major depressive disorder and generalized anxiety disorder. The objective of this study was to evaluate the pharmacokinetic characteristics of escitalopram in the healthy elderly compared with the young.
METHODS: Twelve healthy Korean elderly subjects (> 65 years) and 35 healthy young adults (20-40 years) received single oral dose of escitalopram 20 mg tablet. For pharmacokinetic analysis, serial blood samples were collected up to 48 hours post-dose. Liquid chromatography coupled with tandem mass spectrometry was used to determine the plasma concentrations of escitalopram. The pharmacokinetic parameters were derived using the non-compartmental method.
RESULTS: The mean ages of elderly and young subjects were 68 and 26 years, respectively. The Cmax and the AUC0-t for escitalopram (mean ± SD) in elderly subjects were 23.4 ± 4.7 ng/mL and 564.9 ± 124.4 h*ng /mL; in young adults, 23.0 ± 4.6 ng/mL and 563.5 ± 142.5 h*ng/mL. The geometric mean ratios (90% CI) of the elderly to the young were 1.02 (0.90 - 1.17) and 1.02 (0.88 - 1.18) for Cmax and AUC0-t of escitalopram, respectively. Mean apparent volume of distribution was slightly greater (1175 L vs. 1070 L) and apparent clearance was lower (21.4 L/h vs. 26.5 L/h) in the elderly than in the young, but the differences were not statistically significant (p=0.154 and p=0.172, respectively).
CONCLUSION: Elderly and young adults showed similar pharmacokinetic characteristics of escitalopram after single oral administration. Our results suggest that the effect of aging on the absorption and metabolism of escitalopram would be limited due to its pharmacokinetic characteristics; mainly hepatic elimination, large volume of distribution, and high bioavailability.