Clinical Trial: Evaluation of Lamotrigine on Neuropathic Facial Pain Using fMRI

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Evaluation of Lamotrigine on Neuropathic Facial Pain Using fMRI

Brief Summary: 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).

Detailed Summary: 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.
Sponsor: Pain and Analgesia Imaging and Neuroscience Group

Current Primary Outcome: 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 ]

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**


Original Primary Outcome: blood oxygenation level-dependent (BOLD) changes in neural pain circuitry following treatment with lamotrigine during experimentally induced pain states

Current Secondary Outcome: subjective ratings of pain during MR scanning [ Time Frame: 65-75- Quantitative Sensory Testing, 105-110, 125-130, 145-150 (minutes relative to start) ]

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



Original Secondary Outcome: subjective ratings of pain during MR scanning

Information By: Pain and Analgesia Imaging and Neuroscience Group

Dates:
Date Received: October 19, 2005
Date Started: October 2005
Date Completion:
Last Updated: November 29, 2012
Last Verified: November 2012