Studies of Dextromethorphan and Topiramate to Treat Oral and Facial Pain

Launched by NATIONAL INSTITUTE OF DENTAL AND CRANIOFACIAL RESEARCH (NIDCR) · Nov 3, 1999

Keywords

ClinConnect Summary

Some of the clinical features of trigeminal and other facial neuralgias suggest that these painful disorders may be associated with sensitization of central nervous system neurons. Laboratory evidence has shown that central sensitization can be produced and maintained by excitatory amino acids (e.g. glutamate) acting on neurons at NMDA and AMPA/kainate receptor sites. Given this information, and the need for more effective treatments of orofacial neuropathic pain syndromes, two possible candidates worthy of study are 1) dextromethorphan, an NMDA receptor antagonist and 2) topiramate, an ant...

Gender

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Eligibility criteria

• • Facial neuralgia, not explained by bone, soft tissue or mucosal lesions.
• • Experiencing daily moderate pain or daily paroxysms of pain unremitting for at least 3 months.
• • Previous trial of an antineuralgic medication.
• • Patients entering the study on other analgesic medications must either continue them as a stable regimen throughout the study period or discontinue them 2 weeks prior to starting the initial pain diary.
• • Adults aged 18 to 89.
• Serum laboratory results obtained at study entry:
• • Liver function tests: ALT/AST less than 1.2 times upper limit of normal;
• • Creatinine less than 1.5 times upper limit of normal;
• • Negative serum betaHCG for women of childbearing age.
• • Adequate birth control (e.g., oral contraceptives, Norplant) for all women of child-bearing age.
• • Sufficient cognitive function and English language skills to complete questionnaires and communicate verbally with the nursing staff to permit titration of the study drugs.
• • No presence of a painful condition as severe as, but distinct from their orofacial pain condition.
• • No pregnant or lactating women.
• • Patients must not have end-stage renal or hepatic disease.
• • Patients must not have moderate to severe heart disease (MI within preceding year, unstable angina or congestive heart failure).
• • No signs or symptoms of any central neurologic disorder (including seizures).
• • No psychological/psychiatric disorder as identified by a pre-study entry psychiatric assessment.
• • Patients must not have hypersensitivity or intolerance to dextromethorphan, topiramate or the active placebo.
• • No chronic substance abuse, including alcoholism.
• • Patients must have a primary physician.
• • Subjects must not have received an experimental drug or used and experimental device within 30 days.