Abstract
Fibromyalgia (FM) is a challenging pain syndrome for which no reliable pharmacologic
treatment exists. Recent clinical studies suggest that N-methyl-D-aspartate receptors
might play a role in the pathogenesis of this disorder. To determine whether an intravenous
(IV) ketamine test predicts the response to a therapeutic trial with an oral N-methyl-D-aspartate
receptor antagonist, we performed a low-dose (0.1 mg/kg) IV ketamine infusion on 34
consecutive patients with FM, which was subsequently followed by an oral dextromethorphan
(DX) treatment regimen. As per previous guidelines, the cutoff value for a positive
response to the IV ketamine test was designated to be 67% pain relief, and a positive
response to DX treatment was 50% pain reduction at 4- to 6-week follow-up visits.
The degree of correlation between pain relief with ketamine and DX was highly significant
(Pearson correlation coefficient, 0.66; P < .001). Ten patients responded positively to both ketamine and DX, 19 responded
to neither drug, 3 had a positive response to ketamine but not DX, and 2 obtained
good pain relief with DX but not ketamine. The sensitivity of the IV ketamine test
was 83%, the specificity was 86%, the positive predictive value was 77%, and the negative
predictive value was 91%. An association was also found between the development of
side effects to the two treatments.
Perspective
The response to an IV ketamine infusion was found to predict the subsequent response
to an oral dextromethorphan treatment regimen in fibromyalgia patients, with an observed
agreement of 83%. Considering the refractory nature of fibromyalgia to conventional
pain treatments, the IV ketamine test might enhance patient care by saving time and
reducing unnecessary treatment trials.
Key words
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References
- Intravenous phentolamine test.Pain. 1991; 46: 17-22
- A double-blind, multicenter trial comparing duloxetine with placebo in the treatment of fibromyalgia patients with or without major depressive disorder.Arthritis Rheum. 2004; 50: 2974-2984
- MorphiDex pharmacokinetic studies and single-dose analgesic efficacy studies in patients with postoperative pain.J Pain Symptom Manage. 2000; 19: S31-S36
- The IV ketamine test.Anesth Analg. 2004; 99: 1753-1759
- Ketamine patient-controlled analgesia for dysesthetic central pain.Spinal Cord. 2004; 42: 425-428
- Pregabalin for the treatment of fibromyalgia syndrome.Arthritis Rheum. 2005; 52: 1264-1273
- Neurophysiologic evidence for a central sensitization in patients with fibromyalgia.Arthritis Rheum. 2003; 48: 1420-1429
- Central dysethesia pain after traumatic spinal cord injury is dependent on N-methyl-D-aspartate receptor activation.Neurosurgery. 1995; 37: 1080-1087
- Response to intravenous lidocaine infusion predicts subsequent response to oral mexiletine.J Pain Symptom Manage. 1996; 12: 161-167
- MorphiDex (morphine sulfate/dextromethorphan hydrobromide combination) in the treatment of chronic pain.Pain. 2005; 115: 284-295
- Ketamine reduces muscle pain, temporal summation, and referred pain in fibromyalgia patients.Pain. 2000; 85: 483-491
- Perioperative dextromethorphan reduced postoperative pain after hysterectomy.Anesth Analg. 1999; 89: 399-402
- The promise of N-methyl-D-aspartate receptor antagonists in fibromyalgia.Rheum Dis Clin North Am. 2002; 28: 343-351
- The effects of ketamine-isomers on neuronal injury and regeneration in rat hippocampal neurons.Anesth Analg. 1996; 83: 505-512
- MorphiDex (MS:DM) double-blind, multiple-dose studies in chronic pain patients.J Pain Symptom Manage. 2000; 19: S37-S41
- Ketamine.Anesth Analg. 1998; 87: 1186-1193
- Systemic lidocaine for neuropathic pain relief.Pain. 2000; 87: 7-17
- A qualitative systematic review of the role of N-methyl-D-aspartate receptor antagonists in preventive analgesia.Anesth Analg. 2004; 98: 1385-1400
- A qualitative and quantitative systematic review of preemptive analgesia for postoperative pain relief.Anesthesiology. 2002; 96: 725-741
- High-dose oral dextromethorphan versus placebo in painful diabetic neuropathy and postherpetic neuralgia.Neurology. 1997; 48: 1212-1218
- Motor cortical dysfunction disclosed by single and double magnetic stimulation in patients with fibromyalgia.Clin Neurophysiol. 2000; 111: 994-1001
- Dextromethorphan and memantine in painful diabetic neuropathy and postherpetic neuralgia.Anesthesiology. 2002; 96: 1053-1061
- Fibromyalgia: Are there different mechanisms in the processing of pain? A double blind crossover comparison of analgesic drugs.J Rheumatol. 1997; 24: 1615-1621
- Pain analysis in patients with fibromyalgia.Scand J Rheumatol. 1995; 24: 360-365
- Abnormal sensitization and temporal summation of second pain (wind-up) in patients with fibromyalgia syndrome.Pain. 2001; 91: 165-175
- Effects of the N-methyl-D-aspartate receptor antagonist dextromethorphan on temporal summation of pain are similar in fibromyalgia patients and normal control subjects.J Pain. 2005; 6: 323-332
- Dextrorphan relieves neuropathic heat-evoked hyperalgesia in the rat.Neurosci Lett. 1993; 141: 107-110
- Neuropathic pain sensations are differentially sensitive to dextrorphan.Neuroreport. 1994; 5: 1438-1440
- The predictive lidocaine test in the treatment of neuropathic pain (in Italian).Minerva Anestesiol. 2000; 66: 157-161
- The American College of Rheumatology 1990 criteria for the classification of fibromyalgia.Arthritis Rheum. 1990; 33: 160-172
- Pharmacological classification of central post-stroke pain.Pain. 1997; 72: 5-12
Article info
Publication history
Accepted:
December 30,
2005
Received in revised form:
December 22,
2005
Received:
October 29,
2005
Identification
Copyright
© 2006 American Pain Society. Published by Elsevier Inc. All rights reserved.
