Citalopram is a selective serotonin (5-HT) reuptake inhibitor (SSRI) with an IC50 value of 1.8 nM for 5-HT reuptake in rat brain synaptosomes.1 It is selective for 5-HT reuptake over that of dopamine and norepinephrine (IC50s = >6 mM). Citalopram potentiates headweaving and tremor induced by 5-hydroxy-L-tryptophan (Item No. 20539) in mice (ED50s = 0.61 and 0.66 mmol/kg, respectively). It also acts as an antagonist of nicotinic acetylcholine receptors (IC50 = 0.93 µM).2 Formulations containing citalopram have been used to treat depression. This product is also available as an analytical reference standard (Item No. 23252).WARNING This product is not for human or veterinary use.