What is the primary function of tricyclic antidepressants (TCAs)?

The primary function of tricyclic antidepressants (TCAs) is to block the reuptake of serotonin and norepinephrine. This mechanism increases the levels of these neurotransmitters in the synaptic cleft, thereby enhancing mood and alleviating symptoms of depression. By preventing the reabsorption of serotonin and norepinephrine into the presynaptic neuron, TCAs effectively prolong the action of these neurotransmitters, which is crucial for improving mood and emotional stability in patients diagnosed with depression and sometimes anxiety disorders.

This action is foundational to the therapeutic effects of TCAs, making them effective options in treating major depressive disorder and certain types of anxiety disorders. Their impact on increasing synaptic availability of these key neurotransmitters establishes the basis for their use in clinical practice.