American Society of Regional Anesthesia and Pain Medicine November 2017 - 46

are also managed by the acute pain service by trained faculty.
Conditions commonly treated with intravenous ketamine infusions
include CRPS and refractory neuropathic pain of various causes.
The infusion is typically started at 0.1 mg/kg/hr, then increased
slowly as tolerated to 0.5-0.75 mg/kg/hr, with the entire course
lasting for 5-7 days depending on a patient's response. During this
time, patients are monitored closely, Laboratory test results and
electrocardiogram checked periodically, and side effects treated
in a timely fashion. Benzodiazepines have been used to minimize
its psychotropic side effects. When used in subanesthetic doses,
ketamine is considered safe, and side effects are generally well
tolerated1 or readily treatable. No major complication has occurred
in our patients so far. Similar to the University of Chicago, strong
consideration is given to decreasing opioid analgesics.
ACUTE PAIN
Ketamine given preoperatively, intraoperatively, or postoperatively
has been shown to decrease postoperative pain and reduce
perioperative opioid consumption in opioid-dependent patients.14-16
Ketamine infusions should be considered in the treatment
of refractory acute pain after surgery or from trauma, in the
intensive or intermediate care setting, as well as on the regular
floor, especially for patients who are opioid tolerant. Including
ketamine in the enhanced recovery after surgery protocols is likely
beneficial.
Many questions still remain regarding ketamine. The incidence
and degree of side effects from ketamine depend on dosage.
The existing evidence also suggests that the analgesic effect
of ketamine is both dose9 and duration1,2 dependent. However,
no consensus exists on ketamine infusion protocols regarding
dose, titration, infusion duration, and frequency of repeated
infusions. Randomized controlled trials are needed to answer
these questions. A consensus or guideline on ketamine infusions
is needed, as well. A ketamine registry may be helpful to report
complications.
CONCLUSION
Current evidence has shown that ketamine infusion is effective
in treating chronic and acute refractory pain. It appears ketamine
infusion treatment can be administered on the inpatient ward. A
consensus or guideline on ketamine infusion is needed.
REFERENCES
1.

Niesters M, Martini C, Dahan A. Ketamine for chronic pain: risks and benefits. Br
J Clin Pharmacol 2014;77:357-367. doi: 10.1111/bcp.12094.

Noppers I, Niesters M, Aarts L, Smith T, Sarton E, Dahan A. Ketamine for
the treatment of chronic non-cancer pain. Expert Opin Pharmacother
2010;11:2417-2429. doi: 10.1517/14656566.2010.515978.

Hirota K, Lambert DG. Ketamine: new uses for an old drug? Br J Anaesth
2011;107:123-126. doi: 10.1093/bja/aer221.

Niesters M, Khalili-Mahani N, Martini C, et al. Effect of subanesthetic ketamine
on intrinsic functional brain connectivity: a placebo-controlled functional
magnetic resonance imaging study in healthy male volunteers. Anesthesiology
2012;117:868-877. doi: 10.1097/ALN.0b013e31826a0db3.

Niesters M, Aarts L, Sarton E, Dahan A. Influence of ketamine and morphine on
descending pain modulation in chronic pain patients: a randomized placebocontrolled cross-over proof-of-concept study. Br J Anaesth 2013;110:1010-
1016. doi: 10.1093/bja/aes578.

Woolf CJ. Central sensitization: implications for the diagnosis and treatment of
pain. Pain 2011;152(3 suppl):S2-S15. doi: 10.1016/j.pain.2010.09.030.

Coderre TJ, Katz J, Vaccarino AL, Melzack R. Contribution of central
neuroplasticity to pathological pain: review of clinical and experimental
evidence. Pain 1993;52:259-285.

Okon T. Ketamine: an introduction for the pain and palliative medicine physician.
Pain Physician 2007;10:493-500.

Sigtermans MJ, van Hilten JJ, Bauer MC, et al. Ketamine produces effective and
long-term pain relief in patients with Complex Regional Pain Syndrome Type 1.
Pain 2009;145:304-311. doi: 10.1016/j.pain.2009.06.023.

10. Schwartzman RJ, Alexander GM, Grothusen JR, Paylor T, Reichenberger E,
Perreault M. Outpatient intravenous ketamine for the treatment of complex
regional pain syndrome: a double-blind placebo controlled study. Pain
2009;147:107-115. doi: 10.1016/j.pain.2009.08.015.
11. Kiefer RT, Rohr P, Ploppa A, et al. Efficacy of ketamine in anesthetic dosage
for the treatment of refractory complex regional pain syndrome: an openlabel phase II study. Pain Med 2008;9:1173-1201. doi: 10.1111/j.15264637.2007.00402.x.
12. Eide PK, Jorum E, Stubhaug A, Bremnes J, Breivik H. Relief of post-herpetic
neuralgia with the N-methyl-D-aspartic acid receptor antagonist ketamine:
a double-blind, cross-over comparison with morphine and placebo. Pain
1994;58:347-354.
13. Nikolajsen L, Hansen CL, Nielsen J, Keller J, Arendt-Nielsen L, Jensen TS. The
effect of ketamine on phantom pain: a central neuropathic disorder maintained
by peripheral input. Pain 1996;67:69-77.
14. Safavi M, Honarmand A, Nematollahy Z. Pre-incisional analgesia with
intravenous or subcutaneous infiltration of ketamine reduces postoperative
pain in patients after open cholecystectomy: a randomized, double-blind,
placebo-controlled study. Pain Med 2011;12:1418-1426. doi: 10.1111/j.15264637.2011.01205.x.
15. Loftus RW, Yeager MP, Clark JA, et al. Intraoperative ketamine reduces
perioperative opiate consumption in opiate-dependent patients with chronic
back pain undergoing back surgery. Anesthesiology 2010;113:639-646. doi:
10.1097/ALN.0b013e3181e90914.
16. Barreveld AM, Correll DJ, Liu X, et al. Ketamine decreases postoperative pain
scores in patients taking opioids for chronic pain: results of a prospective,
randomized, double-blind study. Pain Med 2013;14:925-934. doi: 10.1111/
pme.12086.

American Society of Regional Anesthesia and Pain Medicine
2017

Table of Contents for the Digital Edition of American Society of Regional Anesthesia and Pain Medicine November 2017