Intravenous lidocaine relieves spinal cord injury pain: a randomized controlled trial.
BACKGROUND
Neuropathic pain in spinal cord injury is a common challenging therapeutic condition. The current study examines the analgesic effect of the sodium channel blocker lidocaine on neuropathic pain in patients with spinal cord injury and the predictive role of concomitant evoked pain on pain relief with lidocaine.


METHODS
Twenty-four spinal cord injury patients with neuropathic pain at or below the level of injury were randomized and completed a double-blind crossover trial of 5 mg/kg lidocaine and placebo infused over 30 min. Twelve patients reported evoked pain, and 12 patients had no evoked pain. Spontaneous and evoked pains were assessed using a visual analog scale and quantitative sensory testing.


RESULTS
Lidocaine significantly reduced spontaneous pain in all patients (P < 0.01) and in each of the two groups with (P < 0.01) and without (P = 0.048) evoked pain, with no difference in number of responders (pain reduction > or = 33%) between the patients with (n = 6) and without (n = 5) evoked pain. Lidocaine significantly relieved both at-level and below-level neuropathic pain and decreased brush-evoked dysesthesia but not cold allodynia, pinprick hyperalgesia, or pain evoked by repetitive pinprick.


CONCLUSIONS
Lidocaine reduced neuropathic pain at and below the level of injury irrespective of the presence or absence of evoked pain. Results are consistent with a central-acting effect of sodium channel blockers acting on neuronal hyperexcitability. Agents (such as anticonvulsants or antiarrhythmics) with sodium channel-blocking properties may be a treatment option for spinal cord injury pain.
Finnerup
Nanna B
NB
Department of Neurology and Danish Pain Research Center, Aarhus Sygehus, Aarhus, Denmark. finnerup@akhphd.au.dk
Biering-Sørensen
Fin
F
Johannesen
Inger L
IL
Terkelsen
Astrid J
AJ
Juhl
Gitte I
GI
Kristensen
Anders D
AD
Sindrup
Søren H
SH
Bach
Flemming W
FW
Jensen
Troels S
TS
D000328:Adult; D000368:Aged; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008012:Lidocaine / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D010146:Pain / Q000188:drug therapy* / Q000209:etiology*; D010147:Pain Measurement; D013119:Spinal Cord Injuries / Q000150:complications*; D016896:Treatment Outcome
D000779:Anesthetics, Local; D008012:Lidocaine