Dextromethorphan Versus Placebo for Neuropathic Pain

NCT00001344 | Completed Phase 2

• 2 other identifiers: 93011493-D-0114
• Study Type: interventional
• Target: 129
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Diabetic Neuropathies; Herpes Zoster; Neuralgia

Keywords

Diabetes Mellitus; Diabetic Neuropathy; Memantine; NMDA Receptor Antagonists; Neuropathic Pain; Neuropathy; Post-Herpetic Neuralgia; Shingles

Interventions

dextromethorphan DRUG

Eligibility Criteria

• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)

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.

Contact the study team to discuss eligibility requirements. They can help determine if this study is right for you.

Sponsors & Collaborators

• National Institute of Dental and Craniofacial Research (NIDCR): lead

Study Sites (1)

National Institute of Dental And Craniofacial Research (NIDCR)

Bethesda, Maryland, 20892, United States

Location

Related Publications (3)

• Albers GW, Saenz RE, Moses JA Jr, Choi DW. Safety and tolerance of oral dextromethorphan in patients at risk for brain ischemia. Stroke. 1991 Aug;22(8):1075-7. doi: 10.1161/01.str.22.8.1075.

  PMID: 1866755 BACKGROUND

• Bakshi R, Faden AI. Competitive and non-competitive NMDA antagonists limit dynorphin A-induced rat hindlimb paralysis. Brain Res. 1990 Jan 15;507(1):1-5. doi: 10.1016/0006-8993(90)90512-a.

  PMID: 1967971 BACKGROUND

• Choi DW. Dextrorphan and dextromethorphan attenuate glutamate neurotoxicity. Brain Res. 1987 Feb 17;403(2):333-6. doi: 10.1016/0006-8993(87)90070-9.

  PMID: 2881608 BACKGROUND

MeSH Terms

Conditions

Diabetic Neuropathies; Herpes Zoster; Neuralgia; Diabetes Mellitus; Neuralgia, Postherpetic

Interventions

Dextromethorphan

Condition Hierarchy (Ancestors)

Peripheral Nervous System Diseases; Neuromuscular Diseases; Nervous System Diseases; Diabetes Complications; Endocrine System Diseases; Varicella Zoster Virus Infection; Herpesviridae Infections; DNA Virus Infections; Virus Diseases; Infections; Pain; Neurologic Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Glucose Metabolism Disorders; Metabolic Diseases; Nutritional and Metabolic Diseases

Intervention Hierarchy (Ancestors)

Morphinans; Opiate Alkaloids; Alkaloids; Heterocyclic Compounds; Heterocyclic Compounds, Bridged-Ring; Heterocyclic Compounds, 4 or More Rings; Heterocyclic Compounds, Fused-Ring; Phenanthrenes; Polycyclic Aromatic Hydrocarbons; Polycyclic Compounds

Study Design

• Study Type: interventional
• Phase: phase 2
• Purpose: TREATMENT
• Sponsor Type: NIH

Study Record Dates

• First Submitted: November 3, 1999
• First Posted: December 10, 2002
• Study Start: March 1, 1993
• Study Completion: February 1, 2001
• Last Updated: March 4, 2008

Record last verified: 2000-03

Locations

US (1)