Single Dose Preoperative Gabapentin Use in Minimally Invasive Hysterectomy for Acute Pain Management

Multimodal postoperative analgesia after a hysterectomy has been mainly based on a
combination of nonsteroidal anti-inflammatory drugs and opioids. However, adverse effects
including nausea, vomiting, sedation, and pruritus may limit use of opioids. As the side
effects are dose related, minimizing opioid exposure may significantly reduce these risks.
Thus, there has been an interest in evaluating preemptive as well as post-operative
administration of non-opioids. Additional regimens have been suggested to minimize opioid use
and its associated adverse effects including injection of local anesthetics, epidural
analgesia, and anticonvulsants, such as gabapentin or pregabalin.

Gabapentin, a widely used anticonvulsant used for treatment of neuropathic pain, has recently
been suggested to improve postoperative analgesia and reduce opioid requirements. Gabapentin
is thought to modulate calcium channels on the presynaptic nociceptive neurons, which in turn
modulate or inhibit the release of excitatory neurotransmitters from activated nociceptors.
In addition to inhibiting pain transmission, gabapentin may exert an analgesic effect by
activating descending inhibitory noradrenergic pathways.

Many studies have demonstrated the safety and efficacy of gabapentin for perioperative use in
a variety of procedures across disciplines including thoracotomy, laparoscopic
cholecystectomy, tonsillectomy, major orthopedic surgery, cesarean sections, and abdominal
hysterectomy. Several randomized trials have evaluated the effects of gabapentin administered
preoperatively only as well as given pre- and postoperatively for hysterectomy. In a
systematic review of 14 studies conducted between 2004 and 2013, with samples ranging from 40
to 200, investigators identified 8 trials in which gabapentin was administered only
preoperatively to reduce pain associated with abdominal hysterectomy surgery. Analysis of
those data clearly demonstrates that preemptive gabapentin reduced the postoperative visual
analog scale (VAS) pain score by approximately 50% and postoperative use of morphine by
approximately 37%. The incidence of pruritus and dry mouth in those receiving preemptive
gabapentin appeared similar to those receiving placebo, however there was a higher rate of
reported dizziness (not statistically significant) associated with gabapentin. In contrast,
multiple postoperative doses of gabapentin in addition to the preoperative dose was found to
have no significant effect on VAS scores at 24 hours, thus favoring a single preoperative
dose.

Although initial results have been encouraging, uptake of gabapentin in routine clinical use
remains limited due to mixed results and variability between gabapentin protocols, including
dosing and duration. Christiana Care Health System (CCHS) plans to implement the Enhanced
Recovery After Surgery (ERAS) protocol which administers preoperative medications to reduce
postoperative pain, including acetaminophen, celecoxib, dexamethasone, and gabapentin.
Therefore the aim of this study is to assess the efficacy of a single dose of preoperative
gabapentin protocol to reduce acute postoperative pain in women undergoing a minimally
invasive hysterectomy.

Inclusion Criteria:

- undergoing a minimally invasive hysterectomy with surgeons operating within the
Christiana Care Health System at the Newark location only.

- at least 18 years of age

- able to swallow tablets or capsules

Exclusion Criteria:

- liver failure

- renal failure

- prior gastric bypass

- gastroparesis

- recent or current regular gabapentin use

- hypersensitivity to gabapentin, acetominophen, or celecoxib

- procedure is converted to laparotomy for any indication. (Mini-laparotomy for specimen
removal alone will not be excluded.)