Study of NMDA Antagonists and Neuropathic Pain

Study Overview
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Brief Summary
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The aim of this study is to evaluate if memantine or dextromethorphan gave in relay to ketamine maintains or induces a decrease of pain intensity. In clinical, after ketamine cure, clinicians have often difficulties to treat patients in order to maintain analgesia or suggest another treatment if analgesia induced by ketamine was not effective, which occurs in one quarter of patients. It will be very useful for monitoring of painful patients evaluate if memantine or dextromethorphan could be an effective therapeutic alternative in neuropathic pain treatment.

Detailed Description
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The aim of this study is to evaluate if memantine or dextromethorphan gave in relay to ketamine maintains or induces a decrease of pain intensity. In clinical, after ketamine cure, clinicians have often difficulties to treat patients in order to maintain analgesia or suggest another treatment if analgesia induced by ketamine was not effective, which occurs in one quarter of patients. It will be very useful for monitoring of painful patients evaluate if memantine or dextromethorphan could be an effective therapeutic alternative in neuropathic pain treatment.

Official Title
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Antagonists NMDA in Relay to Ketamine in Neuropathic Pain

Conditions
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Neuropathic Pain

Intervention / Treatment
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* Drug: Dextromethorphan (drug used like antitussive)
* Drug: Memantine (drug used in Alzheimer's disease)
* Drug: Placebo (lactose)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: > 18 years old patient suffering chronic neuropathic pain All chronic pain is retained except central or diabetic pain Answering patient at ketamine in pain treatment by investigator, and having already received ketamine Patient who completed before ketamine the following evaluation : DN4, QCD, QDSA, PGIC questionnaires, HAD scale, Leed's sleep evaluation and SF36. Patient who completed at the end of treatment the following evaluation : numerical scale and PGIC Sufficient cooperation and understanding to comply to the requirements of study Acceptance to give a written concert Affiliation at system of French social security Inscription or acceptation of inscription at national register of voluntaries participant at research Exclusion Criteria: Against-indication at memantine or dextromethorphan administration : hypersensitivity at active substance or excipients, hypertension, antecedent cerebrovascular accident, severe cardiac insufficiency Patient with medical or surgical antecedents Patient with progressive disease at balance of inclusion Patient treated by an IMAO Woman in childbearing age not using effective contraceptive method, pregnant or lactating woman Patient who participated in another clinical trial, located in exclusion period or received benefits > 4500 euros during 12 months before the beginning of trial Patient with cooperation and understanding insufficiency to comply to the requirements of protocol Patient with social protection No affiliation at system of French social security

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: memantine<br>The aim of this study is to evaluate if memantine or dextromethorphan gave in relay to ketamine maintains or induces a decrease of pain intensity | Drug: Memantine (drug used in Alzheimer's disease)<br>* The aim of this study is to evaluate if memantine or dextromethorphan gave in relay to ketamine maintains or induces a decrease of pain intensity<br>|
| Experimental: dextromethorphan<br>The aim of this study is to evaluate if memantine or dextromethorphan gave in relay to ketamine maintains or induces a decrease of pain intensity | Drug: Dextromethorphan (drug used like antitussive)<br>* The aim of this study is to evaluate if memantine or dextromethorphan gave in relay to ketamine maintains or induces a decrease of pain intensity<br>|
| Placebo Comparator: placebo<br>The aim of this study is to evaluate if memantine or dextromethorphan gave in relay to ketamine maintains or induces a decrease of pain intensity | Drug: Placebo (lactose)<br>* The aim of this study is to evaluate if memantine or dextromethorphan gave in relay to ketamine maintains or induces a decrease of pain intensity<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Measure of pain by numerical scale |  | at Day 30 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Measure of pain by numerical scale |  | at day 60 and at day 90 | 
| Patient Global Impression if Change (PGIC) |  | at day 30, at day 60 and at day 90 | 
| Leed's slip questionnaire |  | at day 30, at day 60 and at day 90 | 
| Questionnaire of quality of life SF 36 |  | at day 30, at day 60 and at day 90 | 
| DN4 scale |  | at day 30, at day 60 and at day 90 | 
| Neuropathic Pain Symptoms Inventory (NPSI) |  | at day 30, at day 60 and at day 90 | 
| Saint-Antoine questionnaire (QDSA) |  | at day 30, at day 60 and at day 90 | 
| HAD scale |  | at day 30, at day 60 and at day 90 | 
| Questionnaire of identification of pain (QCD) |  | at day 30, at day 60 and at day 90 | 
| Evaluation of cognitive impact (Cantab, Cambridge) |  | at day 30, at day 60 and at day 90 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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NMDA (N-Methyl-D-Aspartate) antagonists, ketamine, memantine, dextromethorphan, Neuropathic pain