Evaluation of Lamotrigine on Neuropathic Facial Pain Using fMRI

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).

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.

Inclusion Criteria:

• 18-60 years of age
• Right-handed non-smokers
• Diagnosed with facial pain
• Continuous pain for more than 3 months
• Spontaneous pain greater than 3 of 10
• Allodynia to brush greater than 5 of 10

Exclusion Criteria:

• Medications
• Depression
• Significant medical problems
• Claustrophobia
• Abnormal EKG
• Significant drug or alcohol history
• Positive drug screen
• Weight greater than 285 lbs
• History of allergy to anticonvulsants
• Tattoos with metallic ink on upper body
• Any neurostimulator devices, or metal cochlear, ocular, or cardiac implants or other metal near vital areas
• Exposure to shrapnel or metal filings
• Other metallic surgical hardware