About citalopramsselective serotonin reuptake inhibitor (ssris), antidepressant.ssmechanism of action of citalopramscitalopram blocks the re-uptake of neurotransmitter serotonin from the synapse to the presynaptic nerve terminal in the cns. this potentiates the action of serotonin (5ht) and it is useful in the treatment of depression. ssindications for citalopramsdepression.sscontra-indications of citaloprams1.hypersensitivity to citalopram, s2.patient on maoi (monoamine oxidase inhibitor) therapy.sspecial precautions while taking citalopram