Amitriptyline hydrochloride (Elavil^®) is a prescription drug licensed for the treatment of depression. Besides treating depression, amitriptyline is also used "off-label" to treat a number of conditions, including ADHD, bulimia, and fibromyalgia. While it is not entirely clear how amitriptyline works, it is known that the drug affects several chemicals in the brain, including serotonin and norepinephrine. Amitriptyline comes in a tablet form that is usually taken one to three times a day, and may be taken with or without food. Seek medical attention immediately if you happen to overdose on amitriptyline. A few of the conditions you should let your healthcare provider know about before taking amitriptyline include schizophrenia, severe anxiety or agitation, diabetes, and heart problems (including heart disease).