How tricyclic antidepressants work

Tricyclic antidepressants ease depression by affecting chemical messengers called neurotransmitters. These chemical messengers communicate between brain cells. Like most antidepressants, tricyclic antidepressants work by causing changes in brain chemistry and communication in brain nerve cell circuitry known to affect mood. This helps lessen the symptoms of depression.

Tricyclic antidepressants block the neurotransmitters serotonin (ser-o-TOE-nin) and norepinephrine (nor-ep-ih-NEF-rin) from being taken back into nerve cells in the brain, a process called reuptake. Blocking reuptake raises the levels of these two neurotransmitters in the brain. Tricyclic antidepressants also affect other chemical messengers, which can lead to some of the antidepressants' side effects.