Pregabalin and Orofacial Neuropathic Pain

The purpose of this study is to determine whether pregabalin can decrease pain and improve quality of life in patients who have nerve pain on the mouth or the face

Neuropathic pain (NP) is defined as pain initiated or caused by a primary lesion or dysfunction in the nervous system. At the trigeminal area where somatosensory nerves are often damaged during dental /maxillofacial interventions, post-operative orofacial neuropathic pain (OFNP) estimated treated prevalence/incidence rates were \~3-12%, with 83% of patients reporting that OFNP started with a dental treatment. Although OFNP is a burden for the society, and a major cause of chronic distress, disability and expenditure of medical resources, clinical trials that assess efficacy of its treatment are scarce. Until today, treatments of OFNP are extrapolated from those issued for neuropathic pain in other body sites. This clinical trial will be the first to evaluate the efficacy, safety, and tolerance of pregabalin in the treatment of OFNP. Based on the results obtained for neuropathic pain on non trigeminal areas, we expect to see positive results, and to provide evidence for effective management of OFNP with an anticonvulsant such as pregabalin.

Eligibility Criteria:
Inclusion Criteria:

* Patients 18 years of age or older, males and females
* history of dental and/or maxillofacial treatment/surgery that may cause nerve injury (e.g. root canal treatment, implant placement, deep restorations, tooth extractions, injection of anesthetics)
* patients who score 12 on the validated self-report version of the Leeds Assessment of Neuropathic Symptoms and Signs pain scale (S-LANSS; Bennett et al. 2005) for extra-oral sites, or 9 for intra-oral sites (the scoring for extra-oral sites is taken as suggested; for intra-oral sites, the 5-point scoring for question 2 has been removed and the score proportionally adjusted, since it is difficult for patients to see color changes in their mouth)
* pain rated 4 or more on a numerical scale (0 being no pain, 10 being the most intense pain imaginable), on a daily basis
* pain lasting more than 6 months
* absence of identifiable organic lesion, inflammation or infection
* normal serum creatinine
* reports that current and previous pain medications failed to provide adequate relief (e.g., analgesic, non-steroidal anti-inflammatories, opioids, antidepressants)
* if currently using medication, acceptance of a wash-out period of at least one week, during which only Tylenol can be used as rescue medication
* able to use the Palm handheld device to report daily pain

Exclusion Criteria:

* lactating, pregnancy (potentially child bearing patients need to have a referral from family physician stating that the patient is not expecting or to be using contraception)
* renal impairment or renal failure (contra-indication to pregabalin)
* congestive heart failure or liver disease
* currently suffering from trigeminal neuralgia
* history of mental disorder, widespread pain or other severe pain conditions that may confound the pain assessment (e.g. depression, chronic fatigue, migraine headaches, fibromyalgia, severe chronic pain conditions)
* intolerance or allergy to gabapentin and pregabalin