May 16, 2016

IV Ketamine for Complex Regional Pain Syndrome and refractory Major Depressive Disorder

Complex regional pain syndrome (CRPS) and refractory major depressive disorder (MDD) pose terrible burdens on those who suffer from them.
CRPS is a special form a neuropathic pain with special unique characteristics. CRPS is also known as Reflex Sympathetic Dystrophy (RSD). CRPS suffers can suffer from ongoing, intractable, pain in an extremity, from the arm or leg feeling hot or cold, from swelling or edema and from loss of range of motion or dystrophy in the arm or leg or changes in the skin, hair and nail beds. There is a wide range of how CRPS presents. It can overtake every aspect of one’s life.
Treatment for CRPS consists of physical therapy, medications and spinal cord stimulation. Not everyone responds.
Refractory MDD, with its sadness, loss of energy and lack of interest in being with other people or doing things, is also a terrible disease. While treatment with antidepressants helps, not everyone responds. Those left behind also pay a terrible price of gloom and depression.
Ketamine infusions are a new treatment for MDD and CRPS. Ketamine is a drug which was first developed as an anesthetic. I have used it as an anesthetic for eye surgery, although newer techniques have replaced ketamine. It works in part by blocking a receptor in the body which is involved with chronic pain, the NMDA receptor. The NMDA receptor is present in both the spinal cord and the brain. Ketamine can lead to synaptogenesis, or the formation of new synapses, and a change in the amount of glutamate. Because of this, ketamine can help with both refractory MDD and with CRPS.
Ketamine infusions seem to have a cumulative effect, so that several infusions, done either every day or every other day, are the preferred treatment. We generally start with three infusions and reassess.
There are many infusion protocols, which are basically described as low dose or high dose. I prefer a low dose infusion, about .15 mg/kg over several hours as a outpatient. High dose infusions can cause unfortunate psychological side effects, including a sense of being out of the body, which can be very unpleasant. These side effects are treated with Versed, a benzodiazepine. Benzodiazepines can interfere with the benefits of ketamine so that we try to avoid them.
I only give ketamine by infusion. It is not very effective as a pill and intranasal ketamine can be very unpleasant
Ketamine infusions are a very exciting and promising treatment for both refractory major depressive disorder and complex regional pain syndrome. It should be given in a monitored setting by an anesthesiologist who is experienced with ketamine.