Study of Sulfasalazine in Treating Painful Neuropathy

Study Overview
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Brief Summary
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The investigators hypothesize that sulfasalazine, an FDA-approved medication for rheumatoid arthritis and ulcerative colitis, may be beneficial in neuropathic pain conditions. In this study, the investigators will evaluate whether sulfasalazine improves pain due to painful peripheral neuropathy.

Official Title
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A Single-center, Randomized, Double-blind Clinical Study to Evaluate the Effect of Sulfasalazine on Painful Neuropathy

Conditions
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Painful Neuropathy

Intervention / Treatment
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* Drug: Sulfasalazine
* Drug: placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Painful neuropathy Michigan Neuropathy Screening Instrument score of 3 or greater no obvious alternative explanation for neuropathy average baseline pain > 4/10 Exclusion Criteria: other severe pain anticipated difficulty weaning off medications past or current psychiatric disorder as determined by Mini International Neuropsychiatric Interview medical contraindication to sulfasalazine not proficient in English (due to heavy use of questionaires) pregnant or breast feeding women

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: Crossover Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: sulfasalazine<br>1 g oral twice daily for 2 weeks | Drug: Sulfasalazine<br> <br> |
| Placebo Comparator: placebo<br>oral placebo pill twice daily for two weeks. | Drug: placebo<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain Score (First Treatment Period) | Average pain score will be the average of daily pain scores (0-10) recorded by the subject in a pain diary during the second week of the two week treatment period. Higher scores are worse (0=no pain, 10=pain as bad as you can imagine). | second week of two week treatment period | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain Score (Using the Crossover Comparison Structure of the Study) | Average pain score will be the average of daily pain scores (0-10) recorded by the subject in a pain diary during the second week of the two week treatment period. Higher scores are worse (0=no pain, 10=pain as bad as you can imagine). | Assessed at end of two week treatment period | 
| Number of Patients With >=50% Pain Reduction (First Treatment Period) | Average pain score will be the average of daily pain scores (0-10) recorded by the subject in a pain diary at baseline and during the second week of the two week treatment period. Higher scores are worse (0=no pain, 10=pain as bad as you can imagine). Percent pain reduction will be calculated from BL to end of treatment period 1 (2 weeks), based on average pain scores at each time point. | second week of two week treatment period | 
| Number of Patients With >=50% Pain Reduction (Using the Crossover Comparison Structure of the Study) | Average pain score will be the average of daily pain scores (0-10) recorded by the subject in a pain diary during baseline and the second week of each of the two week treatment periods. Higher scores are worse (0=no pain, 10=pain as bad as you can imagine). Percent pain reduction will be calculated from BL to end of treatment period 1 (2 weeks) and from end of treatment period 1 to end of treatment period 2 (2 weeks), based on average pain scores at each time point. | Assessed at end of two week treatment period | 
| Physical Functioning Score Assessed Using the Brief Pain Inventory (BPI) Interference Scale (First Treatment Period Only) | The BPI interference items are general activity, mood, walking ability, normal work (including housework), relations with other people, sleep, and enjoyment of life. The seven items are rated from 0 (pain does not interfere) to 10 (pain completely interferes). | Assessed at end of two week treatment period | 
| Physical Functioning Score Assessed Using the Euroquality of Life (EQ-5D) Metrics (First Treatment Period Only) | The EQ-5D physical functioning items are mobility self-care, and usual activities. These three items are rated from 1 (no problems) to 5 (unable). | Assessed at end of two week treatment period | 
| Physical Functioning Score Assessed Using the Brief Pain Inventory (BPI) Interference Scale (Using the Crossover Comparison Structure of the Study) | The BPI interference items are general activity, mood, walking ability, normal work (including housework), relations with other people, sleep, and enjoyment of life. The seven items are rated from 0 (pain does not interfere) to 10 (pain completely interferes). | Assessed at end of two week treatment period | 
| Physical Functioning Score Assessed Using the Euroquality of Life (EQ-5D) (Using the Crossover Comparison Structure of the Study) | The EQ-5D physical functioning items are mobility self-care, and usual activities. These three items are rated from 1 (no problems) to 5 (unable). | Assessed at end of two week treatment period | 
| Emotional Functioning (First Treatment Period Only) | Will be assessed by the Beck Depression Inventory (BDI) total score. The BDI has 21 items, each scored 0-3. Higher values are worse. The total score is the sum of the 21 items and ranges from 0-63. | Assessed at end of two week treatment period | 
| Emotional Functioning (Using the Crossover Comparison Structure of the Study) | Will be assessed by the Beck Depression Inventory (BDI) total score. The BDI has 21 items, each scored 0-3. Higher values are worse. The total score is the sum of the 21 items and ranges from 0-63. | Assessed at end of two week treatment period | 
| Overall Improvement (First Treatment Period Only) | The Patient Global Impression of Change (PGIC) reflects a patient's belief about the efficacy of treatment. Item 1 is as follows: Since beginning treatment at this clinic, how would you describe the change (if any) in ACTIVITY LIMITATIONS, SYMPTOMS, EMOTIONS, and OVERALL QUALITY OF LIFE, related to your painful condition? (tick ONE box) (1=No change (or condition has gotten worse), 2=Almost the same, hardly any change at all, 3=A little better, but no noticeable change, 4=Somewhat better, but the change has not made any real difference, 5=Moderately better, and a slight but noticeable change, 6=Better, and a definite improvement that has made a real and worthwhile difference, 7=A great deal better, and a considerable improvement that has made all the difference). Item 2 is as follows: In a similar way, please circle the number below that matches your degree of change since beginning care at this clinic (0-10 scale): 0= Much better, 5= No change, 10= Much worse. | Will be assessed at end of two week treatment period | 
| Overall Improvement (Using the Crossover Comparison Structure of the Study) | The Patient Global Impression of Change (PGIC) reflects a patient's belief about the efficacy of treatment. Item 1 is as follows: Since beginning treatment at this clinic, how would you describe the change (if any) in ACTIVITY LIMITATIONS, SYMPTOMS, EMOTIONS, and OVERALL QUALITY OF LIFE, related to your painful condition? (tick ONE box) (1=No change (or condition has gotten worse), 2=Almost the same, hardly any change at all, 3=A little better, but no noticeable change, 4=Somewhat better, but the change has not made any real difference, 5=Moderately better, and a slight but noticeable change, 6=Better, and a definite improvement that has made a real and worthwhile difference, 7=A great deal better, and a considerable improvement that has made all the difference). Item 2 is as follows: In a similar way, please circle the number below that matches your degree of change since beginning care at this clinic (0-10 scale): 0= Much better, 5= No change, 10= Much worse. | Will be assessed at end of two week treatment period | 
| Categorical Rating of Pain Intensity (First Treatment Period Only) | Assessed using number of days rated as none, mild, moderate, or severe in pain diary | Assessed at end of two week treatment period | 
| Categorical Rating of Pain Intensity (Using the Crossover Comparison Structure of the Study) | Assessed using number of days rated as none, mild, moderate, or severe in pain diary | Assessed at end of two week treatment period | 
| Breakthrough Treatment (First Treatment Period Only) | Number of days breakthrough pain medication was taken | Assessed during two week treatment period | 
| Breakthrough Treatment (Using the Crossover Comparison Structure of the Study) | Number of days breakthrough pain medication was taken | Assessed during two week treatment period | 
| Missed Medication Dose (First Treatment Period Only) | Number of missed medication doses | Assessed during two week treatment period | 
| Missed Medication Doses (Using the Crossover Comparison Structure of the Study) | Number of missed medication doses | Assessed during two week treatment period |