Multi-day low dose ketamine infusion as adjuvant to oral gabapentin in spinal
cord injury related chronic pain: a prospective, randomized, double blind trial.
Author(s): Amr YM.
Affiliation(s): Anesthesia Department, Tanta University Hospital, Tanta, Egypt.
yasser.amr@gmail.com
Publication date & source: 2010, Pain Physician. , 13(3):245-9
BACKGROUND: Severe, intractable, chronic pain is a significant management problem
for those involved in the long-term care of spinal cord injury (SCI) patients .
Gabapentin, an anticonvulsant, is widely used for treating chronic pain.
Ketamine, an NMDA receptor antagonist, has been available in clinical practice
for 35 years. Its usefulness in pathological pain states is known. Despite this,
no formal research on its effectiveness in treating neuropathic SCI pain exists.
OBJECTIVES: This double-blind study sought to determine the safety and efficacy
of adding a multi-day low dose ketamine infusion to oral gabapentin for treating
chronic pain related to post spinal cord injury.
STUDY DESIGN: Randomized, controlled, double blind trial.
SETTING: Hospital, in-patient setting.
METHODS: Forty patients diagnosed with neuropathic pain secondary to spinal cord
injury were randomized into 2 equal groups. Group I received an 80 mg intravenous
ketamine infusion diluted in 500 cc normal saline over a 5 hour period daily for
one week and 300 mg of gabapentin 3 times daily. Group II received a placebo
infusion and 300 mg of gabapentin 3 times daily (continued) after 300 mg of
gabapentin 3 times daily. Using the visual analogue scale, pain was assessed
prior to treatment, daily following ketamine or placebo infusions for 7 days, and
then weekly for one month after infusion termination. Side effects, specifically
those related to ketamine or gabapentin, were reported.
RESULTS: Both groups demonstrated significantly reduced pain scores compared with
pre-treatment values (P < 0.05). Group I showed significant pain score
improvements over Group II at all measurements (P < 0.0001) during infusion and 2
weeks after infusion termination. There was no statistical difference between the
groups at 3 weeks and 4 weeks after infusion termination (P = 0.54 and P = 0.25
respectively). Both drugs were tolerated by all patients; no side effects
required intervention.
CONCLUSION: Multi-day low dose ketamine infusion as adjuvant to gabapentin in
post-spinal cord injury related chronic pain is safe and efficacious in reducing
pain, but the effect compared to placebo ceased 2 weeks after infusion
termination.
LIMITATIONS: Study size limited to 40 patients.
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