Phenelzine is a prescription medication used to treat depression and anxiety disorders. It is also known as Nardil, a brand name for the drug. There are several synonyms for phenelzine, including its chemical name, 2-phenylethylhydrazine, and its trade names such as Nardelzine, Phenelzin, and Eldepryl. Other related drugs that are in the same class as phenelzine are isocarboxazid, tranylcypromine, and selegiline. These drugs work by increasing the levels of certain neurotransmitters in the brain that regulate mood. Phenelzine is only available through a prescription from a doctor and should be taken as directed to avoid any potential side effects.