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, MD*
o
lu, MD*z, MD
Departments of *Anaesthesiology,
Ear-Nose-Throat Surgery, and
Biostatistics, Trakya University Medical Faculty, Edirne, Turkey
Address correspondence and reprint requests to Alparslan Turan, MD, Trakya University Medical Faculty, Department of Anesthesiology and Reanimation, 22030 Edirne, Turkey. Address e-mail to alparslanturan{at}yahoo.com
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Abstract |
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IMPLICATIONS: Gabapentin has been demonstrated to be effective in different pain models. This study demonstrated that gabapentin decreases intraoperative and postoperative pain scores and analgesic requirements in rhinoplasty or endoscopic sinus surgery patients; however, dizziness may be a handicap for use in ambulatory patients.
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Introduction |
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2 agonists, and cyclooxygenase-2 inhibitors. The multiplicity of mechanisms involved in pain requires a multimodal analgesia regimen, suggesting that a combination of opioid and non-opioid analgesic drugs may improve analgesic efficacy and reduce opioid requirements and side effects after surgery (1).
Gabapentin is a structural analog of 
-aminobutyric acid, which was first developed as an anticonvulsant drug (2). However, subsequent studies established that gabapentin is also effective in diabetic neuropathy (3), neuropathic cancer pain (4), postherpetic neuralgia (5), and inflammatory injury (6). Two studies have indicated a role of gabapentin in acute postoperative pain, but these results are controversial (7,8). Results in one of these studies (7) demonstrated gabapentin to be effective in the early postoperative period by decreasing pain scores and morphine consumption. However, in contrast, a second study (8) found no reduction in pain scores or analgesic requirements in the first 24 h. These results should be validated and other surgical pain models used before a reliable conclusion can be reached. The aim of this study was to determine the analgesic efficacy of gabapentin and compare it with placebo in monitored anesthesia care of patients undergoing rhinoplasty or endoscopic sinus surgery.
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Methods |
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The patients were randomly divided into 2 groups with 25 patients in each. The study design was randomized and double-blinded; patients were randomly allocated according to computer-generated randomization. For premedication, midazolam 0.07 mg/kg and atropine 0.01 mg/kg were administered IM 45 min before the surgical procedure. Control group patients received oral placebo, and gabapentin group patients received 1200 mg of gabapentin (gabapentin 400 mg, Neurontin; Pfizer) 1 h before surgery. The study drugs were prepared by the pharmacy, and an appropriate code number was assigned. After the patients had been taken to the operating room, crystalloid infusion was started through a 20-gauge IV cannula inserted in an appropriate antecubital vein, and the mean arterial blood pressure (MAP), heart rate (HR), and peripheral oxygen saturation were monitored (Cato PM 8040; Dräger, Lübeck, Germany).
After local anesthesia (lidocaine 2% with epinephrine) performed by the same surgeon to the submucopericondrial area, sedation was induced by administering an IV bolus of propofol 0.8 mg/kg and was maintained by continuous infusion of propofol adjusted to maintain sedation at a 2–3 level on the Ramsay scale. The propofol infusion was started with 2 mg · kg–1 · h–1 and titrated according to sedation levels, and total propofol consumption was determined. Patients were evaluated during surgery at 5, 15, 30, 45, and 60 min for sedation levels. All patients received fentanyl 1 µg/kg before surgery. Intraoperative pain assessment was made on the basis of the verbal rating scale (VRS), and postoperative pain assessment was made on a visual analog scale (VAS; 0 = no pain and 10 = worst pain imaginable). VAS and VRS were explained to the patients during the preoperative visit.
Patients were evaluated during surgery at 5, 15, 30, 45, and 60 min for pain assessment according to the VRS. If the VRS score was >4 or on patient request, fentanyl 0.5–1 µg/kg was administered. The total fentanyl consumption by each patient was determined and noted. A blinded observer at 30 min and 1, 2, 4, 6, 8, 12, 16, 20, and 24 h recorded postoperative pain and sedation scores after completion of surgery. Additional analgesic need by each group within 24 h and the time to first analgesic need were determined according to the VAS; when VAS values were >4, diclofenac 75 mg IM was administered and noted. The first analgesic need was regarded as the time elapsed between the administration of the study drug and the administration of an additional analgesic.
Patients were questioned for the first 2 h in the postanesthesia care unit. They were later questioned on the ward every 2 h by an anesthesiology resident not involved in the study about the occurrence of any side effects, such as nausea and vomiting, diarrhea, epigastric discomfort, dizziness, peripheral edema, or headache, and these were recorded if present. On patient request or if nausea and vomiting occurred, ondansetron 4 mg IV was given.
A power analysis suggested that a sample size of 25 patients per group should be adequate to detect a 40% reduction in analgesic consumption with a power of 0.8 ( = 0.05) (9). Descriptive statistics are expressed as mean ± SD unless otherwise stated. All variables were tested for normal distribution by the Kolmogorov-Smirnov test. Student’s t-test was used for comparison of the means of continuous variables and normally distributed data. The Mann-Whitney U-test was used otherwise. Repeated-measures analysis of variance was used for variable differences in groups, and post hoc testing was used for multiple comparisons. Categorical data were analyzed with the 
2 or Fisher’s exact test, as appropriate. Significance was determined at P < 0.05.
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Results |
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The most common side effects observed during the study were dizziness, nausea (16% in both groups), and vomiting (16% versus 12%, respectively). There was a significant incidence of dizziness in the gabapentin group (24%) when compared with the placebo group (4%) (P < 0.05), but there were no significant differences between groups with respect to other side effects.
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Discussion |
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In animal models of nociception, gabapentin reduced mechanical or thermal hyperalgesia (11) and incisional injury (12). Pretreatment with gabapentin also blocked the development of hyperalgesia, suggesting a preventive effect of gabapentin, and had a selective effect on the nociceptive process involving central sensitization (2). Studies have demonstrated that mechanical hyperalgesia surrounding the wound in postoperative patients and experimentally heat-induced secondary hyperalgesia share a common mechanism and that central neuronal sensitization contributes to postoperative pain (13). Thus, drugs such as gabapentin, which have been effective in reducing hyperalgesia in different models of pain, may play an important role in acute postoperative pain in humans.
NSAIDs are commonly used analgesics in ambulatory surgical procedures for decreasing pain and opioid requirements. They are well established, effective, and inexpensive. However, inadequate analgesia and adverse renal, gastrointestinal, and hemostatic effects may limit their use in some groups of patients. Gabapentin is less well established and is likely to be quite expensive. For it to have a useful place, it may ultimately need to be shown to provide better opioid-sparing and/or improved pain relief compared with the NSAIDs and to be associated with fewer adverse events. However, in our study, we determined that 24% of patients encountered dizziness, which may limit the use of gabapentin in ambulatory patients.
One of the limitations of our study is the lack of evaluation of gabapentin in a more painful surgical model with the possibility of long-term pain, which may have been more clinically relevant. Other important limitations of our study are the lack of examination of more than one dose, limited analgesic efficacy, and expense. The pain model we studied is not the most ideal for studying an unproven analgesic. Future investigations for determining the dose-response relationship will be required.
In conclusion, the preoperative single oral administration of gabapentin provided a significant analgesic benefit for intraoperative and postoperative pain relief in patients undergoing ambulatory rhinoplasty or endoscopic sinus surgery; however, gabapentin’s use in ambulatory patients may be limited because of frequent dizziness.
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References |
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olu B, et al. Analgesic effects of rofecoxib in ear-nose-throat surgery. Anesth Analg 2002; 95: 1308–11.This article has been cited by other articles:
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  N. Brogly, J.-M. Wattier, G. Andrieu, D. Peres, E. Robin, E. Kipnis, L. Arnalsteen, B. Thielemans, B. Carnaille, F. Pattou, et al. Gabapentin Attenuates Late but Not Early Postoperative Pain After Thyroidectomy with Superficial Cervical Plexus Block Anesth. Analg., November 1, 2008; 107(5): 1720 - 1725. [Abstract] [Full Text] [PDF]
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 H. J. McQuay, K. H. Poon, S. Derry, and R. A. Moore Acute pain: combination treatments and how we measure their efficacy Br. J. Anaesth., July 1, 2008; 101(1): 69 - 76. [Abstract] [Full Text] [PDF]
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A. C. Van Elstraete, M. Tirault, T. Lebrun, I. Sandefo, J.-C. Bernard, B. Polin, P. Vally, and J.-X. Mazoit The Median Effective Dose of Preemptive Gabapentin on Postoperative Morphine Consumption After Posterior Lumbar Spinal Fusion Anesth. Analg., January 1, 2008; 106(1): 305 - 308. [Abstract] [Full Text] [PDF]
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V. K. F. Kong and M. G. Irwin Gabapentin: a multimodal perioperative drug? Br. J. Anaesth., December 1, 2007; 99(6): 775 - 786. [Abstract] [Full Text] [PDF]
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N. M. Gajraj Pregabalin: Its Pharmacology and Use in Pain Management Anesth. Analg., December 1, 2007; 105(6): 1805 - 1815. [Abstract] [Full Text] [PDF]
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S. Koc, D. Memis, and N. Sut The Preoperative Use of Gabapentin, Dexamethasone, and Their Combination in Varicocele Surgery: A Randomized Controlled Trial Anesth. Analg., October 1, 2007; 105(4): 1137 - 1142. [Abstract] [Full Text] [PDF]
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E. M. Tiippana, K. Hamunen, V. K. Kontinen, and E. Kalso Do Surgical Patients Benefit from Perioperative Gabapentin/Pregabalin? A Systematic Review of Efficacy and Safety Anesth. Analg., June 1, 2007; 104(6): 1545 - 1556. [Abstract] [Full Text] [PDF]
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A. Turan, P. F. White, B. Karamanlioglu, and Z. Pamukcu Premedication with Gabapentin: The Effect on Tourniquet Pain and Quality of Intravenous Regional Anesthesia Anesth. Analg., January 1, 2007; 104(1): 97 - 101. [Abstract] [Full Text] [PDF]
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F. Adam, C. Menigaux, D. I. Sessler, and M. Chauvin A Single Preoperative Dose of Gabapentin (800 Milligrams) Does Not Augment Postoperative Analgesia in Patients Given Interscalene Brachial Plexus Blocks for Arthroscopic Shoulder Surgery Anesth. Analg., November 1, 2006; 103(5): 1278 - 1282. [Abstract] [Full Text] [PDF]
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D. J. Rowbotham Editorial II: Gabapentin: a new drug for postoperative pain? Br. J. Anaesth., February 1, 2006; 96(2): 152 - 155. [Full Text] [PDF]
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A. Turan, G. Kaya, B. Karamanlioglu, Z. Pamukcu, and C. C. Apfel Effect of oral gabapentin on postoperative epidural analgesia Br. J. Anaesth., February 1, 2006; 96(2): 242 - 246. [Abstract] [Full Text] [PDF]
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A. Turan, P. F. White, B. Karamanlioglu, D. Memis, M. Tasdogan, Z. Pamukcu, and E. Yavuz Gabapentin: An Alternative to the Cyclooxygenase-2 Inhibitors for Perioperative Pain Management Anesth. Analg., January 1, 2006; 102(1): 175 - 181. [Abstract] [Full Text] [PDF]
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C. Menigaux, F. Adam, B. Guignard, D. I. Sessler, and M. Chauvin Preoperative Gabapentin Decreases Anxiety and Improves Early Functional Recovery from Knee Surgery Anesth. Analg., May 1, 2005; 100(5): 1394 - 1399. [Abstract] [Full Text] [PDF]
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