Treatment for Complex Regional Pain Syndrome in Colorado
Ketamine is a solution proven safe and effective for the management of
complex regional pain syndrome (CRPS) in outpatient and inpatient settings.
This intervention is often used in the emergency department when the doctor
wishes to avoid narcotics.
What is ketamine?
Sold under the brand name Ketalar, ketamine is a medication used for starting
and maintaining anesthesia. This drug induces a trance-like state, offering
pain relief, memory loss, and sedation. Ketamine effects begin within
5 minutes after injection, and it can last for up to 30 minutes. Ketamine
is used for postoperative pain management, for severe pain related to
CRPS, and for pain relief during surgery. As an analgesic, ketamine is
most effective when combined with a low-dose opioid.
Why is ketamine better than narcotics?
Ketamine has a selective effect on CRPS pain without causing prolonged
sedation or respiratory depression. Ketamine infusions are used because
they do not lead to addiction, physical dependency, or constipation. In
a recent study, low dose intravenous (IV) ketamine was used with an epidural
for pain relief in studied patients. Researchers found the ketamine infusion
eliminated chronic pain and prevented CRPS following surgery. In addition,
the treatment helped prevent depression.
Why is ketamine making a comeback?
For decades, doctors used ketamine for general anesthesia. Because of hallucinations,
the use of ketamine slowed down. Now, pain management specialists are
using low-dose ketamine, which inhibits the NMDA receptors responsible
for central sensitization. It works synergistically with many analgesics,
and hallucinations are rare with low doses.
How does ketamine work?
Ketamine acts as an antagonist of the NMDA receptor. Known actions of the
drug are weak agonist of the μ-opioid and κ-opioid receptors,
activation of AMPA receptors, inhibitor of nitric oxide synthase, and
inhibitor of reuptake of dopamine, norepinephrine, and serotonin. To cause
analgesia, ketamine interacts with a host of other targets, blocking calcium
channels and sodium channels, altering cholinergic neurotransmission,
and affecting antinociceptive pathways.
What is the usual ketamine treatment protocol?
A ketamine infusion protocol consists of deep conscious sedation with ketamine.
The patient is dosed with 0.2mg of glycopyrrolate IV. The starting ketamine
doses is 60 mg/hour. This treatment is given in a controlled medical setting.
Adequate anesthesia for ketamine infusion is achieved when the patient
is in a dissociation state.
Do ketamine infusions work?
In a 2012 retrospective analysis involving 49 patients with severe refractory
pain, researchers evaluated the 360 outpatient ketamine infusions that
occurred over a 5-year timeframe. In the study, immediate reduction of
pain was noted in 59% of patients. In addition, a study of 13 patients
with severe neuropathic pain, researchers found that ketamine infusions
had an 85% success rate, and around half of the patients had pain relief
that lasted for one month.
What are the safety precautions involved with ketamine?
Ketamine will cause drowsiness for up to 24 hours after the infusion. You
should not drive afterwards, and must avoid rigorous activities. Ketamine
can lead to behavior changes, alteration in mental clarity, and mood changes.
Children, teens, pregnant women, and the elderly should not use ketamine.