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

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

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.

Study Overview

• Status: Completed
• Conditions: Pain After Photorefractive Keratectomy
• Intervention / Treatment: Drug: Gabapentin; Drug: Sugar pill

• Study Type: Interventional
• Enrollment (Actual): 40
• Phase: Phase 4

Contacts and Locations

Study Locations

• Mexico
  • Baja California
    • Tijuana, Baja California, Mexico, 22320
      • CODET Vision Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

1. Subjects must be at least 18 years of age
2. Subjects must not have any corneal disease or degeneration
3. Subjects must be candidates for LASIK or PRK refractive surgery

Exclusion Criteria:

1. History of topical ocular medications within 4 weeks prior to enrollment
2. History of conjunctivitis or ocular inflammation within 4 weeks prior to enrollment
3. History of a previous refractive surgery
4. History of previous diagnosis of corneal disease, degeneration, or glaucoma
5. History of autoimmune disease
6. History of oral anti-histamines currently or within 1 week of study enrollment
7. History of systemic anti-inflammatory or pain medication currently or within 4 weeks of study enrollment
8. Use of oral diuretics or betablocker currently or within 1 week of study enrollment
9. Current diagnosis of dry eye
10. Patients whose Best corrected vision is less than 20/20
11. Patients whose target post operative refraction is not plano
12. Pregnant and lactating

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

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

What is the study measuring?

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

Collaborators and Investigators

• Sponsor: Codet Vision Institute

Study record dates

Study Major Dates

• Study Start: April 1, 2010
• Primary Completion (Actual): September 1, 2010
• Study Completion (Actual): November 1, 2010

Study Registration Dates

• First Submitted: April 23, 2010
• First Submitted That Met QC Criteria: August 5, 2010
• First Posted (Estimate): August 9, 2010

Study Record Updates

• Last Update Posted (Estimate): July 29, 2015
• Last Update Submitted That Met QC Criteria: July 27, 2015
• Last Verified: July 1, 2015

More Information

Terms related to this study

• Keywords: Gabapentin; PRK; Refractive surgery; PAIN
• Additional Relevant MeSH Terms: Pathologic Processes; Postoperative Complications; Pain; Neurologic Manifestations; Pain, Postoperative; Physiological Effects of Drugs; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action; Central Nervous System Depressants; Peripheral Nervous System Agents; Analgesics; Sensory System Agents; Excitatory Amino Acid Antagonists; Excitatory Amino Acid Agents; Tranquilizing Agents; Psychotropic Drugs; Anti-Anxiety Agents; Anticonvulsants; Antimanic Agents; Gabapentin
• Other Study ID Numbers: GABA1