Comparison of Gabapentin With Doxepin in the Management of Uremic Pruritus

Study Overview
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Brief Summary
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This is a single blind randomized trial to compare efficacy and side effects of Gabapentin with Doxepin. Hemodialysis patients with uremic pruritus at one dialysis center of Saint George Hospital University Medical Centre were included in this study. Patients were divided into 2 groups to receive either 10 mg Doxepin daily or Gabapentin at a dose of 100mg after each hemodialysis session (increased as tolerated) for 4 weeks, after which patients were treated reversley. Pruritus severity and its effect on quality of life will be assessed by using visual analog scale (VAS), 5-D pruritus scale and dermatology life quality index (DLQI). Include patients will have to fill these forms at baseline and at end of week1, week2 and week4

Detailed Description
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Pruritus is one of the frustrating skin manifestations of advanced renal failure. Many options have been used for the management of uremic pruritus (UP) such as Pregabalin, Gabapentin, Doxepine and Desloratidine. Gabapentin, a GABAergic drug, has been found to be effective in the treatment of uremic pruritus. Doxepin, a potent antihistamine drug, is used orally or topically in many pruritic conditions such as UP, idiopathic pruritus, atopic dermatitis, neurogenic, or psychogenic pruritus and, in the management of the UP in hemodialysis patients. No comparative head to head study between Gabapentin and Doxepine has been conducted to date. The aim of this study was to compare Gabapentin and Doxepin in treatment of uremic pruritus in hemodialysis patients.

Official Title
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Comparison of Gabapentin With Doxepin in the Management of Uremic Pruritus: Pilot Study

Conditions
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Uremic Pruritus

Intervention / Treatment
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* Drug: Doxepin
* Drug: Gabapentin


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: prevalent patients undergoing HD with UP for at least three months any medications with antipruritic effects to be discontinued one week before the study Hemodialysis performed for 3-4 h thrice weekly via a low flux polysulphonedialyser [1.3-1.6 m2 surface areas] using bicarbonate and/or acetate dialysis fluid well controlled Calcium, Phosphorus and iPTH levels Exclusion Criteria: patients labeled high risk of fall (Having a score more than 16/20 using part 1 from Falls Risk Assessment Tool (FRAT) patients taking drugs that interact with doxepin or gabapentin patients with hepatic failure patients with hyperthyroidism patients with narrow angle glaucoma patients with heart block or decompensated heart failure or hypotension (defined as systolic blood pressure less than 90 mmHg) or myocardial infarction in the past three months history of allergy to gabapentin or doxepin uncontrolled psychiatric diseases pregnant patients patients with psoriasis, atopic dermatitis or any other condition that can justify the pruritus

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 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: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Doxepin<br>10 mg Doxepin daily for 4 weeks | Drug: Doxepin<br>* 10 mg Doxepin for 4 weeks<br>* Other names: Adapin;|
| Active Comparator: Gabapentin<br>Gabapentin 100mg after each dialysis session | Drug: Gabapentin<br>* dose of 100mg after each hemodialysis session (increased as tolerated) for 4 weeks<br>* Other names: Fanatrex;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in Worst-itching Visual Analog Scale (VAS) at week 4 | a 10cm horizontal line marked from zero (no pruritus) to 10 (worst possible pruritus). The pruritus will be assessed subjectively and scored as follows: no pruritus (VAS score 0), mild (VAS score 1-3) with episodic and localized pruritus without disturbance in usual work and sleep, moderate (VAS score 4-7) with generalized and continuous pruritus without sleep disturbance and severe (VAS score 8-10) with generalized, continuous pruritus and sleep disturbance. | 1, 2, 4 weeks | 
| Change from baseline in 5-D Itch Scale score at week 4 | multidimensional questionnaire. The five dimensions are degree, duration, direction, disability and distribution. The scores of each of the five domains will be achieved separately and then summed together to obtain a total 5-D score ranging between five (no pruritus) and 25 (most severe pruritus). For the distribution domain, the number of affected body parts is tallied (potential sum 0-16) and the sum is sorted into five scoring bins: sum of 0-21⁄4score of 1, sum of 3-51⁄4score of 2, sum of 6-101⁄4score of 3, sum of 11-131⁄4score of 4 and sum of 14-161⁄4score of 5 | 1, 2, 4 weeks | 
| Change from baseline in Dermatology life quality index (DLQI) at week 4 | 10-Item questionnaire evaluating: impact of skin condition on HRQoL during the past week, symptoms and feeling, daily activities, leisure, work and school, personal relationships, treatment. A Score range from 0 to 30. | 1, 2, 4 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| side effects of each treatment | Number of patients who report side effects while on each treatment | 4 weeks |