Special K is Tough on Pain

September 28, 2009
Janice Arenofsky

Ketamine has captivated physicians and teens ever since 1970 when the FDA approved the drug as a surgical anesthesia, and young adults started getting high on it. First marketed as a veterinary anesthetic, ketamine — which is chemically related to PCP and encourages psychological and physical dependence — quickly caught on with drug abusers. By 1981 the U.S. Department of Health and Human Services recommended ketamine’s reclassification as a controlled substance, but the DEA rejected the idea until 1992 when it received 775 reports of ketamine abuse, including veterinary clinic burglaries and hospital emergency room visits.

Despite an association with date rape and other hallucinatory drugs, infusions of ketamine now represent last-resort therapy for those with the intractable disease known as complex regional pain syndrome. The only drawback to treatment is patients literally may be betting their lives against this unorthodox, and potentially excessive, use of the drug.

“It’s a crappy disease,” said Philip Getson, clinical associate professor of neurology at Drexel University College of Medicine in Philadelphia. The syndrome ranks No. 1 in painful chronic conditions, according to the McGill Pain Index, and its symptoms include unbearable burning and sensitivity, muscle spasms, inflammation and problems with concentration and memory.

Like many pain management experts and despite the dearth of controlled studies, Getson uses ketamine off label. The most powerful of a set of anesthetics known as the NMDA (for N-methyl-D-aspartate) antagonists, ketamine blocks the sensitization process in the central nervous system, allowing pain cells to normalize.

Despite its awful symptoms, complex regional pain syndrome (also called reflex sympathetic dystrophy) remains difficult to diagnose. While the nonprofit RSDHope estimates 1.5 to 3 million with the syndrome in the United States, Getson believes that’s a gross undercount, and that the true number is closer to 6 million, with women experiencing it disproportionately. More…