Isocarboxazid is primarily used as an antidepressant in the treatment of major depressive disorder. It belongs to the class of monoamine oxidase inhibitors (MAOIs), which work by increasing the levels of certain chemicals in the brain that help improve mood and alleviate symptoms of depression. This medication is typically prescribed when other antidepressants have not been effective, due to its potent action and potential side effects. It is also sometimes used in the management of atypical depression, where symptoms may include increased appetite, excessive sleep, and sensitivity to rejection. Patients taking isocarboxazid must follow a strict dietary regimen to avoid interactions with tyramine-rich foods, which can lead to dangerous increases in blood pressure. Additionally, it is crucial to monitor for potential interactions with other medications, as MAOIs can have significant effects on the central nervous system.