THERAPEUTICS

Brands

• Lexapro

Generic?

• Yes

Class

• Selective serotonin reuptake inhibitor (SSRI)

Commonly Prescribed for

(FDA approved in bold)

• Major depressive disorder (adolescent and adult)

• Generalized anxiety disorder

• Obsessive-compulsive disorder

• Post-traumatic stress disorder

• Cataplexy

• Psychosis in dementia

How the Drug Works

• Both citalopram (50:50 S-,R-enantiomer) and escitalopram (S-enantiomer of citalopram) block serotonin reuptake pumps increasing their levels within hours, but antidepressant effect takes weeks. Escitalopram (Ki = 1.1 nM) is 100-fold more potent than the R-enantiomer in inhibiting serotonin reuptake transporter (SERT). No affinity for norepinephrine reuptake transporter (NET), serotonergic, adrenergic, muscarinic, H1, dopamine, opiate, GABA receptors, and Ca2+, Na+, K+, Cl— channels

How Long Until It Works

• May start to see improvement in 1–2 weeks, but usually it takes longer period for full effect

If It Works

• Continue to use and monitor for AEs

If It Doesn't Work

• Increase to highest tolerated dose. Consider adding a second agent or changing to another one

Best Augmenting Combos for Partial Response or Treatment-Resistance

• For some patients, low-dose polytherapy with 2 or more drugs may be better tolerated and more effective than high-dose monotherapy

Tests

• Check ECG for QTc prolongation at baseline and when increasing dose, especially in those with a personal or family history of QTc prolongation, cardiac arrhythmia, heart failure, or recent myocardial infarction

ADVERSE EFFECTS (AEs)

How the Drug Causes AEs

• By increasing serotonin on nontherapeutic responsive receptors throughout the body. Most AEs are dose- and time-dependent

Notable AEs

• Incidence ≥ 5%: insomnia, nausea, fatigue, somnolence, hyperhidrosis, decreased libido, ejaculation delay, and anorgasmia

Life-Threatening or Dangerous AEs

• QTc prolongation, torsade de pointes, and rarely death

• Serotonin syndrome

• Rare activation of mania or suicidal ideation, especially during the initial few months

• Angle-closure glaucoma

• Rare worsening of existing seizure disorders

• Rare hyponatremia and abnormal bleeding