Tricyclic and Tetracyclic Antidepressants (TCAs)

Tricyclic and tetracyclic antidepressants (TCAs) are the first effective antidepressants — designated tri- or tetra-cyclic based on number of rings in chemical structure — but mostly replaced by SSRIs and SNRIs causing fewer side effects. TCAs relieve mood/anxiety symptoms, as well as treat agoraphobia, when others have failed. TCAs affect neurotransmitters by changing brain chemistry and communication in brain nerve cell circuitry that regulates mood. TCAs block reabsorption (“reuptake”) to increase neurotransmitters serotonin and norepinephrine. TCAs also affect other chemical messengers, which can lead to side effects. Approved TCAs are:

• Amitriptyline
• Amoxapine
• Desipramine (Norpramin)
• Doxepin
• Imipramine (Tofranil)
• Nortriptyline (Pamelor)
• Protriptyline
• Trimipramine