Study of the Effect of the Drug Gabapentin on Postoperative Pain and Incidence of Postoperative Nausea and Vomiting

Official Title: “The Effect of Gabapentin on Acute Pain and PONV in Bariatric Surgical Patients”

The purpose of this research study is to evaluate the drug gabapentin (Neurontin®) for its ability to reduce postoperative pain, the need for morphine-like pain medication, and the severity and frequency of postoperative nausea and vomiting in laparoscopic gastric bypass surgery patients.

The occurrence of morbid obesity is at epidemic proportions in the United States.

Laparoscopic gastric bypass is an effective means of safely facilitating patient weight loss and thereby drastically reducing the prevalence and severity of many future health complications [1]. However, managing morbidly obese surgical patients poses certain obstacles for anesthesiologists, including a high incidence of obstructive sleep apnea [2].

Laparoscopic gastric bypass, like all surgical interventions, has associated postoperative challenges including pain management and prevention/control of postoperative nausea and vomiting. To assure the highest patient satisfaction, all areas of patient comfort must be addressed. However, with pain management in morbidly obese patients, caution must be used when administering opioids, as they can have an increasing effect of respiratory depression in patients already at risk due to obstructive sleep apnea [3]. Gastric bypass is also associated with a significant incidence of protracted postoperative nausea and vomiting [4].

Therefore, regimens that address both patient safety and patient comfort are desired.

Gabapentin (Neurontin) is an alkylated analog of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) that has been FDA approved for the treatment of seizures, headaches fibromyalgia and chronic neuropathic pain due to various etiologies [5]. Many randomized controlled trials have been performed with perioperative gabapentin [6-10]. The effect of perioperative administration of gabapentin on postoperative pain and opioid consumption has been extensively studied and several meta-analyses have been published in the last several years examining to overall findings of these studies. The general consensus is that gabapentin has anti-hyperalgesic and opioid-sparing properties and may also reduce the incidence of postoperative nausea and vomiting [5, 11-15]. Most research has shown that gabapentin is beneficial in the treatment of postoperative pain, but some show neither positive nor negative effects. There has been no evidence that gabapentin is detrimental or poses any risks to the postoperative patient. However, gabapentin has not been specifically studied in bariatric surgery. Therefore, the purpose of this study is to explore the hypothesis that perioperative gabapentin has anti-hyperalgesic and opioid-sparing properties, thus increase patient comfort and satisfaction by decreasing pain scores and reducing the adverse effects of opioids, such as postoperative nausea and vomiting.

This is a randomized, double-blind and placebo controlled study, which will be performed in adult laparoscopic gastric bypass patients coming to surgery for morbid obesity. The major end-points of analyses are intraoperative and postoperative opioid requirements and the incidence of nausea and vomiting in the postoperative period.

Intervention(s) in this Clinical Trial

• Drug: Gabapentin
  • Gabapentin 1200 mg (24 cc) by mouth 1 hour prior to surgery AND Gabapentin 300 mg (6cc) by mouth x 6 doses after surgery (0800PM the evening of surgery, 0800AM postoperative day 1, 0200PM postoperative day 1, 0800PM postoperative day 1, 0800AM postoperative day 2, 1200PM postoperative day 2)
• Drug: Placebo
  • Placebo 1200 mg (24 cc) by mouth 1 hour prior to surgery AND Placebo 300 mg (6cc) by mouth x 6 doses after surgery (0800PM the evening of surgery, 0800AM postoperative day 1, 0200PM postoperative day 1, 0800PM postoperative day 1, 0800AM postoperative day 2, 1200PM postoperative day 2)
• Drug: Gabapentin
  • Gabapentin 1200 mg (24 cc) by mouth 1 hour prior to surgery AND Placebo 300 mg (6cc) by mouth x 6 doses after surgery (0800PM the evening of surgery, 0800AM postoperative day 1, 0200PM postoperative day 1, 0800PM postoperative day 1, 0800AM postoperative day 2, 1200PM postoperative day 2)

Arms, Groups and Cohorts in this Clinical Trial

• Active Comparator: 1 Preoperative Gabapentin Liquid
  • Preoperative Gabapentin Elixir (1200 mg) AND Postoperative Placebo Elixir (300 mg x 6 doses)
• Experimental: 2 Preoperative and Postoperative Gabapentin Liquid
  • Preoperative Gabapentin Elixir (1200 mg) AND Postoperative Gabapentin Elixir (300 mg x 6 doses)
• Placebo Comparator: 3 Preoperative and Postoperative Placebo Liquid
  • Preoperative Placebo Liquid (1200 mg) AND Postoperative Placebo Elixir (300 mg x 6 doses)

Primary Measures

• Effect of preoperative and postoperative administration of gabapentin on postoperative opioid requirement.
  • Time Frame: 48 hours
    Safety Issue?: No
• Effect of preoperative and postoperative administration of gabapentin on incidence of postoperative nausea and vomiting.
  • Time Frame: 48 hours
    Safety Issue?: No

Secondary Measures

• Effective of preoperative and postoperative Gabapentin on the incidence of respiratory depression as evidenced by pulse oximetry data
  • Time Frame: 48 hours
    Safety Issue?: Yes

Inclusion Criteria:

• Patients undergoing laparoscopic gastric bypass surgery
• Age > 18 years

Exclusion Criteria:

• Patients under the age of 18 years
• Patients who undergo open gastric bypass
• Patients with a history of chronic pain treated with pregabalin, gabapentin or opioids
• Patients with a history of chronic renal disease (creatinine > 1.3)
• Patients with a history of bleeding gastric ulcer

Gender Eligibility for this Clinical Trial: Both

Minimum Age for this Clinical Trial: 18 Years

Maximum Age for this Clinical Trial: 80 Years

Are Healthy Volunteers Accepted for this Clinical Trial?: No

Lead Investigator: Medical University of South Carolina Other

Overall Clinical Trial Officials and Contacts

Matthew D McEvoy, MD Principal Investigator Medical University of South Carolina  

Information obtained from ClinicalTrials.gov on February 02, 2012

Link to the current ClinicalTrials.gov record. http://clinicaltrials.gov/show/NCT00886236

Study ID Number: HR # 18041 Gaba Bariatric

ClinicalTrials.gov Identifier: NCT00886236

Health Authority: United States: Food and Drug Administration