Effect of Gabapentin Enacarbil on Opioid Consumption and Pain Scores
Condition: Pain
Study type: Interventional

Summary: 
      Opioids are effective analgesics, but cause side effects including sedation, respiratory
      depression, low blood pressure, nausea, and constipation. Gabapentin enacarbil, which is a
      FDA approved drug for post herpetic neuralgia (nerve pain related to shingles) and restless
      leg syndrome, may decrease your need for narcotics and thus decrease the risk of side
      effects. The investigator hopes this study will determine if gabapentin enacarbil decreases
      opioid consumption and pain after surgery.

      Patients having elective hip and knee surgery will be asked to participate in the study.
      Patients will be randomized to Gabapentin enacarbil 600mg twice per day for 5 days or Placebo
      twice per day for 5 days.

      One day prior to surgery the patient will take Gabapentin enacarbil 600mg or placebo 600mg
      twice a day with meals. On the day of surgery, the patient will take Gabapentin enacarbil
      600mg or placebo 600mg two hours before the surgical procedure. Six hours after the
      completion of surgery, the patient will receive Gabapentin enacarbil 600mg or placebo 600mg.
      If the patient is sent home, the patient will be given 6 Gabapentin enacarbil 600mg or
      placebo 600mg pills to take home along with instructions. However, if the patient remains
      hospitalized, on the first day after the surgery, the patient will have pain assessed in the
      morning using a numerical rating score. The patient's quality of recovery will be evaluated
      using a questionnaire and the patient will receive Gabapentin enacarbil 600mg or placebo
      600mg twice a day with meals. The second and third day the patient is in the hospital, the
      patient will have pain assessed in the morning using a numerical rating score and the patient
      will receive Gabapentin enacarbil 600mg or placebo 600mg twice a day with meals. Then, three
      months after surgery, the patient will receive a phone call to follow-up with possible pain
      or discomfort the patient may be feeling.
    

Detailed description: 
      A randomized controlled trial to determine the effect of gabapentin enacarbil on opioid
      consumption and pain scores in patients having primary hip or knee replacement surgery with
      spinal anesthesia.

      Screening visit

        -  Consent will be obtained

        -  Vital Signs

        -  Physical evaluation

        -  Medical History

        -  Laboratory values and medication checked via Epic

        -  Pain scores using numerical rating scores (NRS)

        -  Brief pain inventory (BPI)

        -  Randomization will be to standard management with GEn or to standard management with
           placebo. Patients will be given GEn 600 mg bid or placebo 600 mg bid for 1 preoperative
           day and will receive 600 mg GEn or placebo about 2 hours before surgery and then
           restarted on GEn or placebo 600 mg within 6 hours of surgery, and then 600 mg bid for
           three additional days.

           2 days prior to surgery Phone call will be made to remind patients to take GEn 600 mg
           bid or placebo 600 mg bid

           1 day prior to surgery

        -  vital signs

        -  GEn 600 mg bid or placebo 600 mg bid

        -  monitoring and recording of adverse events

      Day of Surgery

        -  Medical History

        -  Laboratory values and medication checked via Epic

        -  Patients will be given GEn 600 mg or placebo single dose with sips of water 2 hours
           before surgery and then restarted within 6 hours of completion of surgery.

        -  Vital Signs

        -  Social history

        -  Demographic data to be obtained includes height (cm), weight (kg), age (yr), gender,
           (ASA) physical status, and self-declared ethnicity

        -  Individual risk for nausea and vomiting will be determined using the Apfel score.

        -  Monitoring and recording of adverse events

        -  Pain scores using numerical rating scores (NRS) during the PACU stay every 15 minutes
           for the first hour after surgery

      POD 1

        -  GEn 600 mg bid or placebo 600 mg bid

        -  Vital Signs

        -  Monitoring and Recording of adverse events

        -  Pain scores using numerical rating scores (NRS) in the morning

        -  Myles QoR scale to formally evaluate quality of recovery

      POD 2

        -  GEn 600 mg bid or placebo 600 mg bid

        -  Vital Signs

        -  Monitoring and Recording of adverse events

        -  Pain scores using numerical rating scores (NRS) in the morning

      POD 3

        -  GEn 600 mg bid or placebo 600 mg bid

        -  Vital Signs

        -  Monitoring and Recording of adverse events

        -  Pain scores using numerical rating scores (NRS) in the morning

           3 Months after surgery

        -  Phone call will be made to check for any adverse event and with the intention to assess
           chronic pain.

        -  Monitoring and recording of adverse events

        -  Data obtained from electronic medical records will include: operation time, surgery
           type, intraoperative opioid consumption, postoperative opioid consumption in PACU and in
           ward, breakthrough pain medication requirements, pain scores in PACU and ward,
           requirement of antiemetics for nausea and vomiting, requirement of antihistaminic
           medications, requirement of laxatives for constipation, ambulation time, flatus, ileus,
           bowel movements, length of stay and any side effects or complications. Preoperative and
           postoperative laboratory data including but not limited to renal function will also be
           collected from electronic medical records. Patient functionality will also be recorded
           including, bathing, toileting, walking and moving.
    

Intervention name(s): Gabapentin enacarbil; Placebo
Intervention type(s): Drug; Drug
Intervention description(s): 600 mg BID 1 day pre-op and 2 hours before surgery, 6 hours after surgery, 600 mg BID 3 days post-operative; 600 mg BID taken 1 day pre-op and 2 hours before surgery, 6 hours after surgery, 600 mg 3 days post-operative
Other intervention name(s): Xenoport
Intervention MeSH terms: Gabapentin
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment