Which of the following is a tetracyclic antidepressant?

Amoxapine is classified as a tetracyclic antidepressant due to its chemical structure, which has four interconnected rings. Tetracyclic antidepressants, while similar to tricyclic antidepressants (TCAs), have specific differences that affect their pharmacological profiles and side effects.

Amoxapine acts primarily by inhibiting the reuptake of norepinephrine and, to a lesser extent, serotonin, which contributes to its antidepressant effects. Additionally, it has dopaminergic properties, which may provide some unique therapeutic effects compared to other classes of antidepressants.

The other options given are all tricyclic antidepressants. Amitriptyline, doxepin, and nortriptyline share the characteristic three-ring structure, falling under this different subclass. Understanding these distinctions helps clarify the classification and potential actions of these medications within psychiatric treatment.