Doxepin is a tricyclic antidepressant widely used in the treatment of depression, anxiety disorders, and sleep disturbances. It acts mainly by inhibiting the reuptake of serotonin and norepinephrine in the central nervous system. In addition to its antidepressant action, doxepin exhibits strong antihistaminic properties, making it useful in low doses for insomnia and allergic conditions. The drug was developed in the early 1960s as part of extensive research on tricyclic antidepressants. It was first approved for medical use in the late 1960s for the management of mood disorders. Over the years, clinicians recognized its sedative effects, leading to its use in treating sleep disorders. Doxepin also found applications in dermatology for relieving chronic itching. Its versatility has allowed it to remain clinically relevant despite the development of newer antidepressants. Advances in formulation have improved its safety and tolerability. Today, doxepin continues to be used both therapeutically and as a reference substance in pharmaceutical analysis.
