Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Low doses of a common intravenous anesthetic may relieve debilitating pain syndrome


Limited, low-dose infusions of a widely used anesthetic drug may relieve the often intolerable and debilitating pain of Complex Regional Pain Syndrome (CRPS), a Penn State Milton S. Hershey Medical Center researcher found.

"This pain disorder is very difficult to treat. Currently-available therapies, at best, oftentimes only make the pain bearable for many CRPS sufferers," said Ronald E. Harbut, M.D., Ph.D., assistant professor of anesthesiology, Penn State Hershey Medical Center. "In our retrospective study, some patients who underwent a low-dose infusion of ketamine experienced complete relief from their pain, suggesting that this therapy may be an option for some patients with intolerable CRPS."

The study, titled "Subanesthetic Ketamine Infusion Therapy: A Retrospective Analysis of a Novel Therapeutic Approach to Complex Regional Pain Syndrome," was published in the September 2004 issue of Pain Medicine, the official journal of the American Academy of Pain Medicine.

CRPS (type I), also known as Reflex Sympathetic Dystrophy Syndrome (RSD), affects between 1.5 million and 7 million people in the United States and is oftentimes marked by a severe, burning pain that can be very resistant to conventional therapies. The pain frequently begins after a fall or sprain, a fracture, infections, surgery, or trauma. Often present in the limbs with possible later spreading to other parts of the body, patients also may experience skin color changes, sweating abnormalities, tissue swelling, and an extreme sensitivity to light touch or vibrations. The McGill Pain Index rates CRPS as 42 on the scale of 50, with 50 being most severe.

Although much is unknown about CRPS, the pain experienced by patients appears to be caused by over-stimulation of a nerve receptor complex involved in the process of feeling pain. Therefore, efforts have been made to treat CRPS by blocking these receptors. Whereas most pain medications do not effectively block these receptor complexes (often referred to as NMDA-receptors), ketamine does.

The study was initiated by Graeme E. Correll, B.E., M.B.B.S., and involved reviewing the medical records of 33 patients with CRPS treated by Correll. The patients, some of whom had failed to obtain pain relief from conventional therapies, were treated with low-dose inpatient intravenous infusions of ketamine between 1996 and 2002 in Mackay, Queensland, Australia. Ketamine infusions were started at very low rates and were slowly increased in small increments as tolerated by selected patients. The therapy was then continued as long as the patient tolerated the drug and continued to benefit from it. Treatment cycles generally continued until the patient experienced complete pain relief; until initially-obtained relief would not improve any further; or for no more than 48 hours if there was no improvement in pain severity.

Pain was completely relieved for 25 (76 percent) patients, partially relieved for six (18 percent) patients, and not relieved for two (6 percent) patients. Although the relief obtained did not last indefinitely, 54 percent remained completely pain-free for three months or more and 31 percent for six months or more. For 12 patients who received a second treatment, 58 percent experienced relief for one year or more with 33 percent remaining pain-free for more than three years.

The most frequent side effect reported was a feeling of inebriation. Hallucinations occurred in six patients with less frequent side effects including complaints of light-headedness, dizziness and nausea. Liver enzymes were altered in four patients but resolved after therapy.
The exact mechanism of sustained pain relief is unknown, but is currently under study at Penn State Hershey Medical Center. Harbut likened the ketamine treatment to the healing of a broken bone. "If someone breaks a bone and you simply put the two pieces back together, they won’t immediately heal. However, if you add a splint and hold the bones steady for a period of time, and then later take away the splint the bone is healed. I believe that the ketamine treatment does something similar that lends support and allows the nerve cells to heal themselves, so that when you take away the ketamine, the pain is reduced or gone."

Harbut began studying CRPS with Correll during a work assignment Harbut volunteered to take in far northern Queensland, Australia, in the late 1990s. Correll was developing a therapy for CRPS but wanted a collaborator to formally research the effectiveness of the therapy. Harbut brought Correll’s method back to the U.S. where he developed an FDA-approved study protocol (used at the Mayo Clinic Scottsdale) using this method to attempt to treat post herpetic neuralgia, another pain disorder with symptoms somewhat similar to CRPS. At the same time, Harbut met a patient who had suffered with intolerable CRPS for nine years who wanted to try this new therapy. That patient became the first successful treatment of intractable CRPS in the U.S. (A Case Report of this treatment appeared in the June 2002 issue of Pain Medicine.)

"Ultimately, we want to find a way to improve the quality of life for those who suffer with intolerable CRPS, some of whom at times contemplate suicide because of their endless pain," Harbut said. "Although optimistic about these early findings, certainly more study is needed to further establish the safety and efficacy of this novel approach." (A large clinical study is currently planned and under development at Penn State Hershey Medical Center.)

In addition to Harbut and Correll, the team involved in this study included: Jahangir Maleki, M.D., Ph.D., and Edward J. Gracely, Ph.D., Drexel University College of Medicine; and Jesse J. Muir, M.D., Mayo Clinic Scottsdale.

Valerie Gliem | EurekAlert!
Further information:

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Space observation with radar to secure Germany's space infrastructure

Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.

The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...

Im Focus: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

New solar solutions for sustainable buildings and cities

23.03.2018 | Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

Latest News

For graphite pellets, just add elbow grease

23.03.2018 | Materials Sciences

Unique communication strategy discovered in stem cell pathway controlling plant growth

23.03.2018 | Agricultural and Forestry Science

Sharpening the X-ray view of the nanocosm

23.03.2018 | Physics and Astronomy

Science & Research
Overview of more VideoLinks >>>