A fMRI evaluation of lamotrigine for the treatment of trigeminal neuropathic pain: pilot study.
Using functional magnetic resonance imaging (fMRI) methods, we evaluated the effects of lamotrigine vs placebo in a double-blind 1:1 randomized trial. Six patients with neuropathic pain were recruited for the study. All subjects had baseline pain >4/10 on a visual analog scale (VAS) and allodynia to brush as inclusion criteria for the study. Patients underwent two fMRI sessions, with half of the subjects receiving placebo first and half receiving drug first (based on the blinding protocol). Lamotrigine decreased their average pain intensity level from 5.6 to 3.5 on a VAS. All subjects had brush, cold, and heat applied to the affected and mirror-unaffected sides of their face. The results show: 1) in a small cohort, lamotrigine had a significant effect on heat VAS but not on the other stimuli; and 2) contrast analysis of fMRI results for heat stimuli applied to the affected face for lamotrigine vs placebo produced an overall decrease in blood oxygen dependent level signal, suggesting a potential inhibitory effect of the drug on predominantly cortical regions (frontal, parietal, and temporal).
Scrivani
Steven
S
P.A.I.N. Group, Brain Imaging Center, McLean Hospital, Belmont, MA 02478, USA. rmaciewicz@pbsmedicalconsulting.com
Wallin
Diana
D
Moulton
Eric A
EA
Cole
Sadie
S
Wasan
Ajay D
AD
Lockerman
Larry
L
Bajwa
Zahid
Z
Upadhyay
Jaymin
J
Becerra
Lino
L
Borsook
David
D
D000328:Adult; D000588:Amines; D000927:Anticonvulsants / Q000627:therapeutic use*; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology; D003080:Cold Temperature; D018592:Cross-Over Studies; D003509:Cyclohexanecarboxylic Acids; D004311:Double-Blind Method; D005260:Female; D000077206:Gabapentin; D006358:Hot Temperature; D006801:Humans; D000077213:Lamotrigine; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000188:drug therapy* / Q000503:physiopathology; D010147:Pain Measurement; D010919:Placebos / Q000627:therapeutic use; D011569:Psychiatric Status Rating Scales; D014110:Touch / Q000502:physiology; D016896:Treatment Outcome; D014227:Triazines / Q000627:therapeutic use*; D014277:Trigeminal Neuralgia / Q000188:drug therapy* / Q000503:physiopathology; D005680:gamma-Aminobutyric Acid
D000588:Amines; D000927:Anticonvulsants; D003509:Cyclohexanecarboxylic Acids; D010919:Placebos; D014227:Triazines; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin; D000077213:Lamotrigine