Ketamine is an anesthetic agent related to PCP (angel dust). Because of this, it has the tendency to produce hallucinations and paranoid delusions. It has been studied in adults with CRPS and, over 12 weeks, there was a reduction in pain that was most notable the 1st week of therapy, but there was no difference between ketamine and placebo at the end of the study. Even with the reduction in pain, there was no improvement in function. In a study of oral ketamine in 12 children with chronic pain it seemed effective in 5, but did not last longer than 12 months and in the one child who had amplified musculoskeletal pain in this study it was not helpful.
Ketamine comas are not approved in the United States, are very controversial, and have not been proven to have any lasting benefit. Ketamine comas have been associated with paralysis, pneumonia, and pulmonary embolus (which can be life threatening).
There is increasing recognition of liver toxicity as well as prolonged mania.
We had one patient who, years later, was still suffering hallucinogenic flashbacks after having ketamine infusions. We saw another patient who did well initially after a ketamine coma in Germany, but after 40 booster ketamine injections she had such severe pain in her feet that she could not even touch them to the floor. Both of these patients did well in an intense physical and occupational therapy program.
Possible side effects of ketamine include:
- Prolonged Mania
- Psychotic symptoms
- Liver toxicity
- Addiction/drug abuse
- Heart problems (arrhythmia)
- Breathing difficulties
- Ridged muscles
- Extreme pain
- Nausea and vomiting
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