Which of the following medications is classified as a tricyclic antidepressant (TCA)?

Amitriptyline is classified as a tricyclic antidepressant (TCA) because it works by inhibiting the reuptake of norepinephrine and serotonin in the brain, which helps to alleviate symptoms of depression. TCAs are characterized by their three-ring chemical structure and have been used since the 1950s for treating depression and other mood disorders.

In contrast, the other medications listed—fluoxetine, citalopram, and sertraline—are selective serotonin reuptake inhibitors (SSRIs). These medications primarily target serotonin reuptake in the brain and are commonly prescribed for depression and anxiety but do not have the same chemical structure or mechanism of action as TCAs. Understanding the classification of medications is crucial in pharmacology and guides appropriate clinical use in treating various psychiatric conditions.