Tricyclic antidepressants are a class of medications approved by the FDA for treating depression. While not approved by the FDA for treating pain, they may play a role in back pain management. They are prescribed off-label for nerve pain, and in this role are called adjuvants. By interacting with chemicals in the nervous system, tricyclic antidepressants adjust the way the pain signals are transmitted. One pill can yield both antidepressant and pain-relieving effects, but the way in which these effects are brought about are not related to one another. Also, if you are taking a tricyclic antidepressant for pain, your dose will likely be lower than if you are taking it for depression.
The effects of tricyclic antidepressants are not limited to depression and pain. These drugs affect a number of body systems. Because of this, a range of side effects can occur. The side effects may be manageable (dry mouth, constipation, drowsiness) or prohibitive (rapid heat beat, aggravation of glaucoma, increased risk of seizures, to name a few.) It is important that you have an honest discussion with your doctor about any other conditions you may have so that she can accurately determine if this type of pain medication is a good fit for you.
Tricyclic antidepressants are one of a few types of antidepressants used to manage chronic back pain. Others, often known as novel antidepressants, includes bupropion, venlafaxine, and duloxetine (brand name Cymbalta). Like tricyclics, some of the novel antidepressants are effective for managing neuropathic back pain. The good news is that they also incur fewer side effects than tricyclic antidepressants. But a number of novel antidepressants are so targeted to chemical interactions relating to depression that unless an underlying psychological problem is responsible for your pain, they may not be effective at relieving it.
Other types of adjuvant pain medications used to treat chronic back pain are those in the anti-convulsant class. (They are also called anti-seizure medications.) Anti-seizure medications for chronic back pain work about as well as antidepressants, but come with different safety and side effect warnings. This type of drug may make a better choice for seniors and the elderly because there are less safety concerns than with antidepressants.
Tricyclic antidepressants, especially amitriptyline, are the most cost-effective of all off-label medications prescribed for back pain. There is also evidence suggesting that tricyclic antidepressants may help relieve pain due to fibromyalgia. Currently pregabalin (brand name Lyrica) and the anti-depressant duloxetine (brand name Cymbalta) are the only medications approved by the FDA to treat fibromyalgia.
Maizels, Morris, MD, & McCarberg, Bill, MD (2005). Antidepressants and Antiepileptic Drugs for Chronic Non-Cancer Pain. American Family Physician, 71. http://www.aafp.org/afp/20050201/483.html
Gould, Harry J., III, MD. Understanding Pain: What it is Why it Happens, and How it's Managed. New York: Demos, 2007. Print
Fink, K., MD, Director Pain Services. National Rehabilitation Hospital, Washington, DC. Telephone Interview. March 9 2009.