Evaluation of Lamotrigine on Neuropathic Facial Pain Using fMRI
The aim of this project is to evaluate the effects of the anticonvulsant drug lamotrigine (trade name Lamictal) on neuropathic facial pain or neuralgia using functional magnetic resonance imaging (fMRI).
|Study Design:||Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Investigator)
Primary Purpose: Treatment
|Official Title:||Evaluation of Lamotrigine on Neuropathic Facial Pain Using fMRI|
- blood oxygenation level-dependent (BOLD) changes in neural pain circuitry following treatment with lamotrigine during experimentally induced pain states [ Time Frame: 75-90 (mins relative to start) Anatomical Scan, 90-150 fMRI ] [ Designated as safety issue: No ]fMRI scans acquired Stimuli Type: Brush Stimulation Regions: Face (V2) Right and Left Sides Rating: Pain/ unpleasantness fMRI scans acquired Stimuli Type: Cold, threshold -1°C Stimulation Regions: Face (V2) Right and Left Sides Rating: Pain/ unpleasantness **Extra time allotted for probe repositioning** fMRI scans acquired Stimuli Type: Heat, threshold +1°C Stimulation Regions: Face (V2) Right and Left Sides Rating: Pain/ unpleasantness **Extra time allotted for probe repositioning**
- subjective ratings of pain during MR scanning [ Time Frame: 65-75- Quantitative Sensory Testing, 105-110, 125-130, 145-150 (minutes relative to start) ] [ Designated as safety issue: No ]
QST (Quantitative Sensory Testing) Thresholds
Stimuli Type: Brush Stimulation Regions: Face (V2) Right and Left Sides Rating: Pain/ unpleasantness Stimuli Type: Cold, threshold -1°C Stimulation Regions: Face (V2) Right and Left Sides Rating: Pain/ unpleasantness Stimuli Type: Heat, threshold +1°C Stimulation Regions: Face (V2) Right and Left Sides Rating: Pain/ unpleasantness
|Study Start Date:||October 2005|
|Study Completion Date:||July 2008|
|Primary Completion Date:||July 2008 (Final data collection date for primary outcome measure)|
Active Comparator: Lamotrigine
The drug lamotrigine or placebo will be given for 9 weeks prior to imaging session 1. A rescue drug, Gabapentin, will be provided during both arms of the study for pain control. Patients will taper off the Gabapentin 2 weeks before each scan date. After a taper and washout period lamotrigine or placebo (cross over) will be administered. At the end of the trial (after imaging session 2), a taper for drug/placebo will be given. Patients will be required to maintain a pain diary during the study, documenting the perceived effects of the drug on the severity of their pain and keeping track of their subjective pain ratings day to day. Patients will also complete the McGill Pain Questionnaire at each visit.
: 25mg and 50mg tablets
Currently there are no pharmacological agents that can control neuropathic pain akin to the efficacy of antibiotics for bacterial infection. All current neuropathic pain drugs have approximately the same efficacy of less than 30% in controlled trials, and many of these drugs do not have known mechanisms of action. fMRI studies may provide insight into how brain circuitry is altered by chronic pain, and how these drugs act on altered circuitry. The trigeminal system in particular offers unique advantages for studying such alterations, including a large central representation and high degree of somatotopy. The administration of lamotrigine to neuropathic pain patients in conjunction with fMRI will allow us to compare subjective ratings of pain with objective measures of neural activity during increased conditions of allodynia/hyperalgesia.
|United States, Massachusetts|
|McLean Hospital Neuroimaging Center, 115 Mill Street|
|Belmont, Massachusetts, United States, 02478|
|Principal Investigator:||David Borsook, M.D., Ph.D.||Mclean Hospital|