Amitriptyline falls under the class of tricyclic antidepressants. It is used in the treatment of depression. It helps improve one's moods, as well as relieving anxiety and tension. It is also known to increase energy levels. Amitriptyline achieves this by affecting the balance of specific chemicals in the brain. It may also be used to treat nerve pain, migraine headaches, and eating disorders such as bulimia. However, this is only when prescribed by your doctor.