A Prospective Randomized Double Blind Trial to Assess the Effect of a Single Preoperative Dose of Gabapentin on Postoperative Opioid Consumption in Patients Undergoing Rhinoplasty

Study Design A prospective randomized double blind study will be conducted to assess the effect of a single preoperative dose of gabapentin on postoperative opioid consumption within the first 72 hours when compared to oral placebo in patients undergoing rhinoplasty at The Ohio State University Wexner Medical Center.

Preoperative Period After assessing patients' eligibility on the day of the surgery and written informed consent is obtained, subjects will be randomized into two groups: placebo group (group I) and gabapentin group (group II).

Pain level will be assessed and recorded at baseline using the verbal NPRS. A single dose of study medication will be administered within 2 hours before scheduled surgery time. Patients randomized to group I will receive matched oral placebo whereas patients randomized to group II will receive 900 mg of oral gabapentin. Once provided by pharmacy, the study medication will be administered by a blinded nurse in the preoperative area.

Intraoperative Period General anesthesia with desflurane and fentanyl will be provided in all patients. Other anesthetic procedures including intraoperative monitoring, muscle relaxation, endotracheal intubation, mechanical ventilation, fluid management, and the use of intravenous dexamethasone will be carried out in accordance with standard procedures. Ondansetron (4 mg) will be used as PONV prophylaxis in all patients 30 minutes before the end of the surgery. Moreover, an orogastric tube (OGT) will be used for stomach emptying at the end of the surgery and before the emergence of anesthesia.

Postoperative period Closure time will be recorded as T0. The time elapsed from PACU arrival until the first opioid dose (either oral or IV) will be recorded. Once in PACU, patients will receive IV fentanyl as pain rescue medication if required and PACU length of stay will be also recorded. After patients are considered stable based on clinician assessment and willingness to start oral intake, a treatment with oral acetaminophen 650 mg scheduled every 6 hours and oral oxycodone (5-10 mg) as needed (PRN) will be initiated for all patients.

Anesthesiologists and researchers evaluating postoperative outcomes will be blinded. The verbal NPRS will be used to assess postoperative pain level at PACU arrival, and every 30 minutes until hospital discharge. After discharge, pain levels will be recorded by patients in their diary at T6, T12, T24 (6, 12, and 24 hours after T0 respectively), and before requiring breakthrough medication (oxycodone) until postoperative day (POD) 7.

Follow-up phase Patients will be discharged home as per standard of care with oral acetaminophen 650 mg scheduled every 6 hours and a prescription for oral oxycodone 5-10 mg every 4 hours as needed (PRN). At discharge, the patient will be instructed to record his oral opioid consumption (oxycodone) and NPRS scores before each oxycodone dose until POD 7 (see attached diary).

A follow-up visit will be matched with the standard postsurgical visit at POD 7 in order to collect the diary, and count the remaining pills from the oxycodone bottle. Adverse events (AEs) including nausea and vomiting will be assessed and documented during the whole study participation.

Inclusion criteria

• Patients males and females ≥ 18 years old
• Patients providing a written informed consent in English language
• Patients scheduled to undergo rhinoplasty under general endotracheal anesthesia

Exclusion criteria

• Patients with known allergies to medications described in this study: acetaminophen, gabapentin, and opioids (morphine, fentanyl, hydromorphone, oxycodone)
• Patients with chronic use of opioids due to any medical/surgical condition or those receiving any opioid medication within the 48 hours before surgery
• Use of gabapentin and/or pregabalin within the last 14 days prior to surgery
• Use of acetaminophen within the last 7 days prior to surgery
• Hepatic disease as documented in patient past medical history
• Medical history of autoimmune/neurodegenerative disease
• Pregnancy or breast feeding
• Patients with history of alcohol or substance abuse/dependency within the last 6 months
• Patients with previous participation in this study or receiving any investigational product within the last 30 days
• Patients under legal protection or prisoners