Escitalopram is a Selective Serotonin Reuptake Inhibitor (SSRI)
Yes, escitalopram (Lexapro) is definitively classified as a Selective Serotonin Reuptake Inhibitor (SSRI).
Pharmacological Classification Evidence
Escitalopram is clearly identified as an SSRI in multiple authoritative guidelines:
The FDA drug label explicitly states: "Escitalopram tablets contains escitalopram oxalate, an orally administered selective serotonin reuptake inhibitor (SSRI)" 1
The American Academy of Pediatrics specifically lists escitalopram (Lexapro) among SSRIs: "SSRIs (eg, fluoxetine [Prozac], paroxetine [Paxil], sertraline [Zoloft], citalopram [Celexa], escitalopram [Lexapro], and fluvoxamine [Luvox]) are now the most frequently used drugs to treat depression" 2
The American Academy of Child and Adolescent Psychiatry confirms that medications from the SSRI class currently marketed in the United States include "citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, and vilazodone" 2
Mechanism of Action
Escitalopram functions as an SSRI through the following mechanisms:
It inhibits the presynaptic reuptake of serotonin in the brain, thereby increasing serotonin availability at the synaptic cleft 1
The FDA label states: "The mechanism of antidepressant action of escitalopram, the S-enantiomer of racemic citalopram, is presumed to be linked to potentiation of serotonergic activity in the central nervous system (CNS) resulting from its inhibition of CNS neuronal reuptake of serotonin (5-HT)" 1
It is highly selective for serotonin transporters with "minimal-to-nonexistent affinity for other receptor sites" 3
Escitalopram is "at least 100-fold more potent than the R-enantiomer with respect to inhibition of 5-HT reuptake and inhibition of 5-HT neuronal firing rate" 1
Clinical Significance
Escitalopram is the S-enantiomer of citalopram, and research indicates:
It is the therapeutically active component of citalopram, with studies showing that 10 mg/day of escitalopram is as effective as 40 mg/day of citalopram 3
It represents a refinement in SSRI therapy due to its increased selectivity 3
It has "a highly selective and potent, dose-dependent inhibition of the human serotonin transporter" 4
Potential Adverse Effects
As with other SSRIs, escitalopram can cause:
Common side effects including dry mouth, nausea, diarrhea, headache, somnolence, insomnia, and dizziness 2
In newborns exposed prenatally, SSRIs including escitalopram may cause "crying, irritability, tremors, poor suck, feeding difficulty, hypertonia, tachypnea, sleep disturbance, hypoglycemia, and seizures" 2
In conclusion, escitalopram is definitively classified as an SSRI based on its pharmacological mechanism of action, clinical applications, and recognition in multiple authoritative guidelines.