A Comparison of Pregabalin (Lyrica®) to Placebo in Pain Relief After Photorefractive Keratectomy (PRK) Surgery

Study Overview
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Brief Summary
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The purpose of this study is to compare the efficacy of pregabalin to placebo for postoperative pain control after photorefractive keratectomy.

Detailed Description
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Study subjects will be taken from a standard group of typical candidates for PRK surgery including active duty and DoD (Department of Defense) beneficiaries. Prior to being approached for the study, all patients will have had a previous desire for surgery and had a pre-operative evaluation indicating healthy ocular status. Patients scheduled for PRK surgery will be briefed on the purpose of the study and invited to participate at the preoperative appointment. After the consent process, patients will be randomized in a 1:1 fashion to receive either oral pregabalin 75mg twice daily or placebo for pain control, in addition to the standard care treatment of as needed Percocet and tetracaine ophthalmic drops. Subjects will be evaluated daily for 4 days post-operatively for subjective pain assessment, adverse drug events and compliance, use of concomitant medications as well as monitoring of healing time. Quality of life will be measured at baseline and post-op day 2 when the peak of pain is anticipated. Analysis will be performed to detect an approximate 10% improvement in pain scores. Secondary outcomes will include measuring healing time, quality of life and use of rescue medications.

Official Title
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A Comparison of Pregabalin (Lyrica®) to Placebo in Postoperative Pain Relief of Patients Status-post Photorefractive Keratectomy: A Double-masked Randomized Prospective Study

Conditions
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Postoperative Pain

Intervention / Treatment
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* Drug: pregabalin
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy ocular status Stable preoperative refractive anisometropia Consented to the PRK surgical procedure Exclusion Criteria: Pregnant or breastfeeding Diagnosed with autoimmune disease or diabetes Patients with a known adverse reaction or hypersensitivity to gabapentin or pregabalin Patients only desiring PRK on one eye Patients with history of drug use/abuse/addiction Patients who are on chronic pain medications Patients currently taking anti-epileptic, antidepressant and/or anti-psychotic medications Patients with a history of suicidality Patients with chronic renal insufficiency (defined as estimated creatinine clearance less than 30ml/min or Scr ≥ 2.0) 10) Patients who have experienced angioedema, or have heart failure

Ages Eligible for Study
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Minimum Age: 21 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: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: pregabalin<br>Oral Pregabalin 75 mg capsule twice daily administered prior to PRK and continued for 5 days | Drug: pregabalin<br>* 1 capsule (75 mg) by mouth twice daily starting two hours prior to surgery and continuing 4 days postoperatively.<br>* Other names: Lyrica;|
| Placebo Comparator: Placebo<br>Oral placebo capsule (Lactose) twice daily administered prior to PRK and continued for 5 days | Drug: Placebo<br>* 1 capsule by mouth twice daily starting two hours prior to surgery and continuing 4 days postoperatively.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Clinical Efficacy | Determine if clinical efficacy is achieved with pregabalin administered prior to PRK and continued for 5 days. This will be evaluated using the short-form McGill pain questionnaire (SF-MPQ). Primary efficacy is assessed on 100mm Visual Analog Scale (VAS); total range is 0 to 100. A score closer to zero indicates a better outcome of less pain. | 5 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| PPI Score | Determine if clinical efficacy is achieved with pregabalin administered prior to PRK and continued for 5 days. This will be evaluated using the short-form McGill pain questionnaire (SF-MPQ). Secondary efficacy is assessed with present pain intensity (PPI) score. Scale is 0 (no pain) to 5 (excruciating pain) | 5 days | 
| Total MPQ Score | Determine if clinical efficacy is achieved with pregabalin administered prior to PRK and continued for 5 days. This will be evaluated using the short-form McGill pain questionnaire (SF-MPQ). Secondary efficacy is assessed using the Total MPQ Score. Scale minimum is 0 (no pain) to maximum of 45 (severe pain). A higher score indicates a worse outcome. | 5 days | 
| Quality of Life - BPI | Determine if there was an improvement in the patient's functional health and well-being associated with pregabalin compared to standard of care as assessed by Brief Pain Inventory-short form (BPI-SF). Data was assessed on the day of surgery (Day 0) and at the expected peak of pain, postop Day 2 in the morning. Scale is minimum 0 (no pain) to maximum of 10 (pain as bad as you can imagine). A higher score indicates a worse outcome. | 5 days | 
| Clinical Efficacy 2 | Determine if there was a reduction in the need for use of rescue pain medications, Percocet and tetracaine, in those subjects who received pregabalin. Total number of doses was collected. A higher number of doses required indicates a worse outcome. | 5 days | 
| Epithelial Healing Time | Determine if there was a reduction in healing time associated with pregabalin as seen with daily slit-lamp observation. Epithelial defect was measured at post-operative day 3, 5, 7, and 9 in each eye. A higher number of days required for healing indicates a worse outcome. | 5 days or more | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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photorefractive keratectomy, excimer laser, PRK, pain, postoperative, pregabalin