Dextromethorphan Versus Placebo for Neuropathic Pain

March 3, 2008 updated by: National Institute of Dental and Craniofacial Research (NIDCR)
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.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

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.

Study Type

Interventional

Enrollment

129

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Maryland
      • Bethesda, Maryland, United States, 20892
        • National Institute of Dental and Craniofacial Research (NIDCR)

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Patients must be over 18 years of age.

Patients must have a definite diagnosis of diabetic neuropathy or post herpetic neuralgia or a diagnosis of neuropathic pain of various etiologies other than diabetic neuropathy or post herpetic neuralgia.

Duration of symptoms must be at least 3 months.

Severity of pain must be at least mild, if constant; or at least moderate, if intermittent and at least 2 hours duration a day.

Patients using tricyclics, narcotics, or antiseizure medications, must keep the drug dosages constant throughout the study.

No patients with unstable disease process; i.e., angina pectoris, accelerated hypertension, recent stroke or transient cerebral ischemia, uncontrolled seizures.

No pregnant or lactating women. Women of child bearing potential must use birth control pills, intrauterine device, or barrier contraceptive devices.

No history of significant drug abuse or PCP use. No history of IV drug abuse, prescription drug abuse, or alcoholism.

No significant liver or kidney disease.

No MAO inhibitors.

No cognitive impairment or language difficulty as judged by difficulty completing pain diary, medical history, or telephone conversation.

Patients must not have any other chronic pain condition that gives them pain greater than the neuropathy pain.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Institute of Dental and Craniofacial Research (NIDCR)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

March 1, 1993

Study Completion

February 1, 2001

Study Registration Dates

First Submitted

November 3, 1999

First Submitted That Met QC Criteria

December 9, 2002

First Posted (Estimate)

December 10, 2002

Study Record Updates

Last Update Posted (Estimate)

March 4, 2008

Last Update Submitted That Met QC Criteria

March 3, 2008

Last Verified

March 1, 2000

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 930114
  • 93-D-0114

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Diabetic Neuropathies

Clinical Trials on dextromethorphan

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Ethiopia

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe