Citalopram
Celexa
Selective Serotonin Reuptake InhibitorGeneric availableTDM data
The mechanism of action of citalopram is unclear, but is presumed to be related to potentiation of serotonergic activity in the central nervous system (CNS) resulting from its inhibition of CNS neuronal reuptake of serotonin (5-HT).
Compare Citalopram →FDA-Approved Indications
- Major depressive disorder in adults
Common Off-Label Uses
- Generalized anxiety disorder
- Panic disorder
- Social anxiety disorder
- OCD
- PTSD
- PMDD
- Body dysmorphic disorder
What Sets This Drug Apart
- Dose-dependent QTc prolongation: 8.5 msec at 20 mg, 18.5 msec at 60 mg — the most significant QTc signal among SSRIs
- Maximum dose capped at 40 mg/day (20 mg for CYP2C19 poor metabolizers, CYP2C19 inhibitors, elderly >60, hepatic impairment)
- Racemic mixture; S-enantiomer (escitalopram) is the active form — citalopram is at least 8x more potent than its metabolites
- Only FDA-approved for MDD in adults — narrowest indication set of any SSRI
- Weak CYP inhibitor overall (1A2, 2D6, 2C19 — all weak); no CYP3A4, 2C9, or 2E1 inhibition
- Longest half-life (~35 hours) of any SSRI except fluoxetine
- Henssler 2024 any-symptom discontinuation rate 0.19 (95% CI 0.05–0.48, k=2) — low point estimate but very small study count
- Cipriani 2018 MDD response OR 1.52 (95% CrI 1.33–1.74), acceptability OR 0.94 (0.80–1.09) — in the 'more tolerable' group
- Somnolence 18% (vs 10% placebo) — notably higher than escitalopram (~6%)
- Failed two pediatric MDD trials (n=407); no pediatric indication
Boxed Warning
SUICIDAL THOUGHTS AND BEHAVIORS