The Role of Gabapentin in Postoperative Pain and Epithelialization After Photorefractive Keratectomy

Study Overview
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Brief Summary
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The primary aims of this study are to determine if treatment with Gabapentin taken systemically (oral tablets) in patients who have photorefractive keratectomy (PRK) surgical treatments reduces post surgical neuropathic pain and discomfort. The investigators main Hypothesis is that gabapentin given prior to and after refractive surgery prevents central sensitization and local allodynia.

Official Title
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The Role of Gabapentin in Postoperative Pain and Epithelialization After Photorefractive Keratectomy A Prospective, Randomized, Double Blinded, Placebo Controlled Study

Conditions
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Pain After Photorefractive Keratectomy

Intervention / Treatment
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* Drug: Gabapentin
* Drug: Sugar pill


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Subjects must be at least 18 years of age Subjects must not have any corneal disease or degeneration Subjects must be candidates for LASIK or PRK refractive surgery Exclusion Criteria: History of topical ocular medications within 4 weeks prior to enrollment History of conjunctivitis or ocular inflammation within 4 weeks prior to enrollment History of a previous refractive surgery History of previous diagnosis of corneal disease, degeneration, or glaucoma History of autoimmune disease History of oral anti-histamines currently or within 1 week of study enrollment History of systemic anti-inflammatory or pain medication currently or within 4 weeks of study enrollment Use of oral diuretics or betablocker currently or within 1 week of study enrollment Current diagnosis of dry eye Patients whose Best corrected vision is less than 20/20 Patients whose target post operative refraction is not plano Pregnant and lactating

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: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: GABAPENTIN<br>Group of patients treated with oral gabapentin | Drug: Gabapentin<br>* Gabapentin PO. (300MG) 1 capsule the night before surgery, q12hrs the day of surgery and q8hrs for the firt 3 postoperative days.<br>|
| Placebo Comparator: PLACEBO<br>Group given the placebo capsules | Drug: Sugar pill<br>* Sugar pill. One capsule given the night before surgery, q12hrs on the day of surgery and q8hrs for the first 3 postoperative days.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain at moment of examination | Numerical Visual scale questionnaire. a scale from 0-10 where 0 is the least amount of pain and 10 being the most pain felt was recorded Every patient will be examined every 24 hours until complete healling which usualy takes place between 3 and 4 days; after complete healing the next and last examination is performed at the 7th postoperative day | 24 hours postoperatively | 
| Average pain for the previous 24 hour period, | Numerical visual scale questionnaire, a scale from 0-10 where 0 is the least amount of pain and 10 being the most pain felt was recorded | assesed at 24 hours | 
| Maximum pain intensity for the previous 24 hour period | In a scale from 0-10 where 0 is the least amount of pain and 10 being the most pain felt was recorded. | Assesed at 24 hours postoperatively | 
| Pain at moment of examination | Numerical Visual scale questionnaire. a scale from 0-10 where 0 is the least amount of pain and 10 being the most pain felt was recorded Every patient will be examined every 24 hours until complete healling which usualy takes place between 3 and 4 days; after complete healing the next and last examination is performed at the 7th postoperative day | 48 hours postoperatively | 
| pain on examination | Numerical Visual scale questionnaire. a scale from 0-10 where 0 is the least amount of pain and 10 being the most pain felt was recorded Every patient will be examined every 24 hours until complete healling which usualy takes place between 3 and 4 days; after complete healing the next and last examination is performed at the 7th postoperative day | 72 hours postoperatively | 
| pain on examination | Numerical Visual scale questionnaire. a scale from 0-10 where 0 is the least amount of pain and 10 being the most pain felt was recorded Every patient will be examined every 24 hours until complete healling which usualy takes place between 3 and 4 days; after complete healing the next and last examination is performed at the 7th postoperative day | 96 hours ostoiperatively | 
| Pain at moment of examination | Numerical Visual scale questionnaire. a scale from 0-10 where 0 is the least amount of pain and 10 being the most pain felt was recorded Every patient will be examined every 24 hours until complete healling which usualy takes place between 3 and 4 days; after complete healing the next and last examination is performed at the 7th postoperative day | postoperative day 7 | 
| Average pain for the previous 24 hour period | Numerical Visual scale questionnaire. a scale from 0-10 where 0 is the least amount of pain and 10 being the most pain felt was recorded Every patient will be examined every 24 hours until complete healling which usualy takes place between 3 and 4 days; after complete healing the next and last examination is performed at the 7th postoperative day | Assesed at 48 hours | 
| Average pain during the previous 24 hour period | Numerical Visual scale questionnaire. a scale from 0-10 where 0 is the least amount of pain and 10 being the most pain felt was recorded Every patient will be examined every 24 hours until complete healling which usualy takes place between 3 and 4 days; after complete healing the next and last examination is performed at the 7th postoperative day | Assesed at 72 hours postoperatively | 
| Average pain for the last 24 hours period | Numerical Visual scale questionnaire. a scale from 0-10 where 0 is the least amount of pain and 10 being the most pain felt was recorded Every patient will be examined every 24 hours until complete healling which usualy takes place between 3 and 4 days; after complete healing the next and last examination is performed at the 7th postoperative day | Assesed at 96 hours postoperatively | 
| Average pain since last examination | Numerical Visual scale questionnaire. a scale from 0-10 where 0 is the least amount of pain and 10 being the most pain felt was recorded Every patient will be examined every 24 hours until complete healling which usualy takes place between 3 and 4 days; after complete healing the next and last examination is performed at the 7th postoperative day | Assesed on postopertive day 7 | 
| Maximum pain intensity for the previous 24 hour period | Numerical Visual scale questionnaire. a scale from 0-10 where 0 is the least amount of pain and 10 being the most pain felt was recorded Every patient will be examined every 24 hours until complete healling which usualy takes place between 3 and 4 days; after complete healing the next and last examination is performed at the 7th postoperative day | Assesed at 48 hours postoperatively | 
| Maximum pain intensity for the previous 24 hour period | Numerical Visual scale questionnaire. a scale from 0-10 where 0 is the least amount of pain and 10 being the most pain felt was recorded Every patient will be examined every 24 hours until complete healling which usualy takes place between 3 and 4 days; after complete healing the next and last examination is performed at the 7th postoperative day | Assesed at 72 hours postoperatively | 
| Maximum pain intensity for the last 24 hour period | Numerical Visual scale questionnaire. a scale from 0-10 where 0 is the least amount of pain and 10 being the most pain felt was recorded Every patient will be examined every 24 hours until complete healling which usualy takes place between 3 and 4 days; after complete healing the next and last examination is performed at the 7th postoperative day | Assesed at 96 hours postoperatively | 
| Maximum pain intensity since the last examination | Numerical Visual scale questionnaire. a scale from 0-10 where 0 is the least amount of pain and 10 being the most pain felt was recorded Every patient will be examined every 24 hours until complete healling which usualy takes place between 3 and 4 days; after complete healing the next and last examination is performed at the 7th postoperative day | Assesed on the 7th postoperative day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time required for complete healing | Slit lamp observation of the epithelial defect and time until removal of contact lens. | Evaluated each day until complete healing | 
| Visual acuity | Snellen Chart | every day until complete healing and at the 7th day postop | 
| Foreign body sensation | Numerical visual scale, In a scale from 0-10 where 0 is the least amount of foreign body sensation and 10 being the most. | Every 24 hours until complete healing and at the 7th day postop | 
| Light sensitivity | Numerical visual scale, in a scale from 0-10 where 0 is the least amount of light sensitibity and 10 being the most. | Every 24 hours until complete healing and at the 7th day postop | 
| Tearing and watery eyes | Numerical visual scale questionaire, In a scale from 0-10 where 0 is the least amount of tearing and 10 being the most. | Every 24 hours until complete healing and at the 7th day postop | 
| Eye discomfort | Numerical visual scale questionnaire, In a scale from 0-10 where 0 is the least amount of discomfort and 10 being the most. | Every 24 hours until complete healing and at the 7th day postop | 
| Dizziness | Numerical visual scale, scale from 0-10 where 0 is the least dizzy and 10 being the most. | Every 24 hours until complete healling and at the 7th day postop | 
| lethargy | Numerical visual scale, In a scale from 0-10 where 0 is the least lethargic and 10 is the most. | Every 24 hours until complete healing and at the 7th day postop | 
| Headache | Numerical visual scale, In a scale from 0-10 where 0 is the least amount of headache and 10 being the most severe headache felt. | Every 24 hours until complete healing and at the 7th day postop | 
| Gastro-intestinal symptoms | Numerical visual scale, In a scale from 0-10 where 0 is the least amount of symptoms and 10 being the most symptoms. | Every 24 hours until complete healing and at the 7th day postop | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Refractive surgery, PRK, PAIN, Gabapentin