Small molecule
PubChem CID 2771
Citalopram
Celexa
- Mechanism of action
- Selective serotonin reuptake inhibitor (SSRI)
- In plain language
- Eases depression by blocking the brain's reabsorption of serotonin, and it's the parent 50/50 molecule mixture from which the more potent single-molecule drug escitalopram was later purified out.
- How it works
- Citalopram is a selective serotonin reuptake inhibitor (SSRI) marketed as the racemic (+/-) mixture of R- and S-citalopram. Per FDA labeling, its mechanism is presumed to involve potentiation of serotonergic activity in the CNS through inhibition of neuronal reuptake of serotonin at the presynaptic serotonin transporter (SERT), increasing synaptic serotonin availability. Pharmacologic studies show the racemate's SERT-inhibitory activity resides almost entirely in the S-enantiomer: S-citalopram binds SERT with roughly 30- to 40-fold higher affinity than R-citalopram, and the R-enantiomer appears to partially antagonize the S-enantiomer's binding through an allosteric interaction with the transporter. This is the pharmacologic basis for escitalopram — the purified S-enantiomer, also on this site — being developed and marketed as a distinct SSRI at a lower milligram dose than racemic citalopram. Citalopram causes dose-dependent QTc-interval prolongation, and FDA labeling caps dosing at 40 mg/day due to this risk.
- Therapeutic applications
- Per FDA-approved labeling, citalopram (Celexa) is indicated for the treatment of major depressive disorder in adults.
- Class
- Small molecule
- Therapeutic area
- CNS / Psychiatric
View
Related compounds