Dextromethorphan Versus Placebo for Neuropathic Pain

Completed · Phase 2

Conditions studied: Diabetic Neuropathies, Herpes Zoster, Neuralgia

In brief

In our current clinical trial, we are comparing the effects of two NMDA receptor antagonists to placebo in patients with painful distal symmetrical diabetic neuropathy or post-herpetic neuralgia. The treatments in this three-period crossover study are dextromethorphan, up to 920 mg/day (about 8 times the antitussive dose), memantine, 30-50 mg/day, and placebo. Memantine is an NMDA antagonist used in Europe to treat Parkinson's disease and Alzheimer's disease. The underlying hypothesis, based on studies of painful neuropathies in animal models, is that neuropathic pain is caused largely by sensitization of central nervous system neurons caused by excitatory amino acid neurotransmitters, acting largely through NMDA receptors. A previous small trial of dextromethorphan suggested efficacy in diabetic neuropathy pain. The study requires one visit to the NIH outpatient Pain Research Clinic, and consists of three 9-week treatment periods. Patients who respond to one of the medications will be invited to participate in further controlled studies of the medication followed by up to several years of open-label treatment under continued observation.

Key facts

Study ID
NCT00001344
Run by
National Institute of Dental and Craniofacial Research (NIDCR)
People needed
129
Starts
1993-03-01
Expected to finish
2001-02-01
Last updated by the study team
2008-03-04

Who can join

Age: any. Sex: any. Healthy volunteers: not accepted.

Where it is running

Full record on ClinicalTrials.gov

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