By Ginevra Liptan, MD
Editor’s Note: Ginevra Liptan, MD is both a fibromyalgia patient and physician specialist. Her new book The FibroManual: A Complete Fibromyalgia Treatment Guide for You…And Your Doctor releases May 3, 2016.
A recent CBS news segment featured a doctor in Florida talking about his success treating fibromyalgia with intravenous (IV) ketamine, a medication usually used for surgical anesthesia. One of his patients described that her fibromyalgia pain was “virtually eliminated” by this treatment.
I wasn’t surprised to hear this. A few years back, several of my fibromyalgia patients reported mysterious pain reduction that lasted for several weeks after they underwent seemingly unrelated surgeries. In each case, I found the only consistent feature was not the type of surgery they had, but that that they had all received IV ketamine as part of their anesthesia during surgery.
The fascinating—and exciting part—is that although IV ketamine is used in anesthesia to block pain signals only temporarily, for some fibromyalgia patients it seemed to trigger a more long-lasting “cool down” of the pain signals, allowing for a period of sustained pain relief without any further medication. We don’t understand exactly how ketamine might trigger sustained pain relief. We do know that ketamine’s primary action is to block certain receptors (NMDA) that act to transmit pain signals. These NMDA receptors are massively overstimulated in fibromyalgia.
So it’s possible that a large IV dose may act to reset the system; like rebooting a computer (Have you tried turning it on and off again, the magic words any IT service person will tell you!). However, ketamine also activates opiate receptors and boosts levels of other pain lowering chemicals like serotonin, norepinephrine, and dopamine. It may be a combination of these actions that results in a pain “reboot.”
Ketamine’s medical usage has largely been curtailed because it can also be a drug of abuse. As a street drug it is known as Special K. However, resistance to medical usage is slowly changing, as more and more studies show benefit for illnesses that don’t have many treatment options. IV Ketamine has been most well studied as a treatment for resistant depression. A Washington Postarticle called ketamine for depression “the most significant advance in mental health in more than half a century.”
IV ketamine is slowly becoming more accepted and available for severe depression. In fact, several academic medical centers, including Yale University, the University of California at San Diego, the Mayo Clinic and the Cleveland Clinic, have begun offering IV ketamine treatments off-label for severe depression. This treatment has also shown great promise in complex regional pain syndrome, characterized by severe pain, swelling, and skin changes usually occurring after an injury.
Ketamine given intravenously is a more potent pain reliever than morphine for fibromyalgia. http://www.ncbi.nlm.nih.gov/pubmed/8610220
In one study, more than half of the patients who were treated with IV ketamine reported at least a 50% decrease in their pain levels. http://www.ncbi.nlm.nih.gov/pubmed/10781923 But these two studies only looked at immediate reduction of pain.
To assess for long-term benefits, other researchers gave one dose of IV ketamine and then tracked fibromyalgia pain levels after two weeks and then again at eight weeks. At two weeks, some residual pain benefits remained, but these had disappeared by week eight. http://www.ncbi.nlm.nih.gov/pubmed/21482474 There may be dosage or timing issues at play here, as extrapolating from research on CRPS sustained pain benefit was seen only after subjects received a series of several IV ketamine infusions over several weeks. http://www.ncbi.nlm.nih.gov/pubmed/23703410
For now, IV ketamine for fibromyalgia remains very much an experimental treatment. This means it is usually not covered by insurance and can be expensive. But as research progresses, this is slowly changing and more pain clinics are starting to offer this treatment.
Source: National Pain Report