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

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.

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