This article is one in a series on Medications for Pain…  What are your choices?  How do various medications work?  What are the pros and cons?  How about side effects?  (Discuss these ideas with your doctor.  Don’t make any changes to your treatment by yourself.)

The class of medication we’ll look at today is Antidepressants, which are medications originally used to treat depression, and are good for anxiety as well as pain.  Within this class, there are:

• Tricyclic antidepressants (TCA’s), which include Amitriptyline (Elavil) and Nortriptyline.
• SNRI’s (Serotonin-Norepinephrine Reuptake Inhibitors), which include Cymbalta, Effexor (specifically at higher doses), and a new one, Savella.
• SSRI’s (Selective Serotonin Reuptake Inhibitors), which include Zoloft, Prozac, Lexapro, etc.

It’s important to know that antidepressants work for pain even if you’re not depressed or anxious.  They have an independent pain-reducing effect.  So if your physician recommends an antidepressant, it’s not implying that your pain is all in your head, or that you’re just anxious or depressed.

That being said, anxiety and depression often go along with chronic pain, unfortunately.  So if that’s true for you, a good thing about these medications is that they also help depression, anxiety and PTSD (Post Traumatic Stress Disorder – PTSD can occur if there was a traumatic cause to your pain, such as a car or work accident).  As well, because sedation is a common side effect of antidepressants, many of them can help the sleep disturbance that accompanies pain.

Effect of Antidepressants:  All antidepressants work to change neurotransmitters in the brain.  Neurotransmitters are those chemicals by which nerves communicate with one another.  TCA’s and SNRI’s increase both serotonin and norepinephrine, while SSRI’s only increase serotonin.  TCA’s also affect many other chemical systems, including the anticholinergic system (causing drying of your mouth, constipation and sedation), histamine (drying, sedating), and systems causing cardiac and blood pressure effects.

It seems that the combination of serotonin and norepinephrine effect is what’s crucial in decreasing pain.

Medical Studies:

• TCA’s:  Out of 126 studies of TCA’s for pain, 95% of the studies showed that TCA’s were effective for reducing pain.
• SNRI’s:  Out of 10 studies, 100% showed that SNRI’s were effective.
• SSRI’s:  Of 39 studies, 33% showed that SSRI’s were effective.

So again, this demonstrates that the medications which affect both serotonin and norepinephrine work best at helping with pain.

Uses of Antidepressants:  Let’s look at some examples of these medications for specific pain disorders.  Cymbalta is FDA-approved to treat the pain that can accompany diabetes, called Diabetic Peripheral Neuropathy.  Savella is approved for Fibromyalgia.  Paxil is helpful for chronic daily headache and migraines.  We do know that SSRI’s are generally not helpful for neuropathic (nerve) pain.

Common Side Effects:

• TCA’s:  sedation, constipation, weight gain; less often heart arrhythmia, decreased blood pressure
• SNRI’s:  nausea, sedation
• SSRI’s:  headache, nausea, anxiety

In this series:

1. Medication for Pain Series 2009
2. Aspirin, Motrin and NSAIDS
3. Anticonvulsants
4. Antidepressants
5. Anesthetics
6. NMDA receptor antagonists (e.g. Ketamine)
7. Muscle relaxants
8. Blood Pressure Medication
9. Narcotics (Opiates)
10. Anti-Psychotics
11. Medication Advances Coming Soon
12. Research Advances