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

Not Applicable

Completed

Conditions: Postoperative Pain

Interventions: Drug: Placebo
Drug: pregabalin

Registration Number: NCT01097577

Lead Sponsor: 59th Medical Wing

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

Detailed Description: 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.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 130

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

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Placebo	Placebo	Oral placebo capsule (Lactose) twice daily administered prior to PRK and continued for 5 days
pregabalin	pregabalin	Oral Pregabalin 75 mg capsule twice daily administered prior to PRK and continued for 5 days

Primary Outcome Measures

Name	Time	Method
Clinical Efficacy	5 days	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.

Secondary Outcome Measures

Name	Time	Method
Epithelial Healing Time	5 days or more	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.
PPI Score	5 days	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)
Quality of Life - BPI	5 days	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.
Clinical Efficacy 2	5 days	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.
Total MPQ Score	5 days	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.