What are tricyclic antidepressants, and how do they work?
Tricyclic antidepressants (TCAs) are a class of antidepressant medications that share a similar chemical structure and biological effects. Scientists believe that patients with depression may have an imbalance in neurotransmitters, chemicals that nerves make and use to communicate with other nerves. Tricyclic antidepressants increase levels of norepinephrine and serotonin, two neurotransmitters, and block the action of acetylcholine, another neurotransmitter. Scientists believe that by restoring the balance in these neurotransmitters in the brain that tricyclic antidepressants alleviate depression. In addition to relieving depression, tricyclic antidepressants also cause sedation and block the action of histamine.
