Gabapentin as a Pre-emptive Analgesic in Oral and Maxillofacial Surgical Procedures

Pain after surgery is a significant acute clinical symptom. It is associated with quality of post-operative recovery, time spent in the hospital, post-discharge care and readmissions, morbidity, psychosocial distress, and cost of care. The management of acute postsurgical pain primarily consists of a multimodal approach consisting of opioids, non-steroidal anti-inflammatory drugs (NSAIDs), acetaminophen, and local anesthetics. The associated adverse effects often limit the use of such multimodal pharmacotherapy. Opioids have excellent analgesic properties, however are associated with poor adverse-effects profile. They have been associated with nausea, vomiting, somnolence, and urinary retention. Such adverse-effects may decrease the quality of post-operative recovery, increase patient post-surgical management, and overall cost of care. Moreover, in patients undergoing oral and maxillofacial surgical procedures, such adverse-effects may be further potentiated due to placement of reconstructive plates, screws, and maxillomandibular fixation. In order to improve post-surgical quality of care, researchers have been looking for alternative modalities for the management of acute post-surgical pain. One of such modalities has been use of preemptive analgesic therapy. Preemptive analgesia is defined as a treatment modality that is initiated before a traumatic event, such as, surgical incision or tissue manipulation is introduced. Gabapentin is an antiepileptic drug that has been used in the management of painful neuropathies, such as, diabetic poly-neuropathy, post-herpetic neuralgia, and trigeminal neuropathy. Gabapentin has antiallodynic and antihyperalgesic properties with only a minor effect on normal nociception. It reduces the hyperexcitability of dorsal horn neuron induced by tissue injury, as well as, central sensitization induced after trauma and surgery. Gabapentin has been studied extensively as a preemptive analgesic in various non-craniofacial surgeries. In a systemic review and meta-analysis on the pre-operative administration of gabapentin during various surgical procedures, Tiippana et al reported the opioid-sparing effect during the first 24 h after a single dose of gabapentin 300-1200 mg, administered 1-2 h preoperatively, ranged from 20% to 62%. Authors further concluded that the combined effect of a single dose of gabapentin was a reduction of opioid consumption equivalent to 30 +/- 4 mg of morphine (mean +/- 95% confidence interval) during the first 24 h after surgery. In another meta-regression analysis authors reported that gabapentin reduced opioid related adverse effects, such as nausea, vomiting, and urinary retention (Numbers needed to treat (NNT) 25, 6, and 7, respectively). In a systematic review and meta-analysis, consisting of randomized controlled trials of women who underwent a total abdominal hysterectomy, under general anesthesia, it was concluded that preemptive administration of gabapentin was effective in decreasing postsurgical pain scores, narcotic consumption, and nausea and vomiting episodes. Similar reduction in postsurgical pain scores, narcotic consumption, and adverse effects were seen after other surgical procedures, such as, breast surgery, spinal surgery, orthopedic surgical procedures, and amputation surgery. However, no such data is available for major oral and maxillofacial surgical procedures

Primary and secondary aims are as following:

Primary aims:

1. To determine the difference in the intensity of pain, post-operatively, at 6 hours, 12 hours, 24 hours, and 72 hours between participants pre-operatively administered gabapentin versus those pre-operatively administered a placebo medication.
2. To determine the difference in the total opioid consumption at 24 and 72 hours post-operatively, among participants pre-operatively administered gabapentin versus those pre-operatively administered a placebo medication.
3. To evaluate the difference in the time to first rescue analgesic post-operatively, among participants pre-operatively administered gabapentin versus those pre-operatively administered a placebo medication.
4. To determine the difference in the incidence of adverse effects within first 24 hours and 72 hours post-operatively between participants pre-operatively administered gabapentin versus those pre-operatively administered a placebo medication.

Secondary aims: