- Escitalopram, the S-(+)-enantiomer of citalopram, is a selective serotonin reuptake inhibitor with potent effects in animal models predictive of antidepressant and anxiolytic activities. Sánchez, C., Bergqvist, P.B., Brennum, L.T., Gupta, S., Hogg, S., Larsen, A., Wiborg, O. Psychopharmacology (Berl.) (2003)