A Comparative Preemptive Use of Pregabalin With Placebo For Post-Operative Pain – A Randomized Double Blind Study

Abstract

Background and objectives

Pain is a personal, subjective experience that involvesensory, emotional and behavioral factors. Prevention and treatment of post-operative pain continues to be a major challenge in post–operative pain care. According to international association for the study of pain is defined as “pain is an unpleasant sensory and emotional experience associated with actual or potential damage. Good pain control after surgery is important to prevent negative outcomes such as hypertension, tachycardia, myocardial ischemia, decrease in alveolar entilation and poor wound healing. Although many analgesic drugs are used for post-operative pain, many patients still complain from suboptimal pain. Anti-hyperalgesic drugs can treat postoperative pain by preventing CNS pain hypersensitivity example of this drug is Pregabalin. Pregabalin is a potent ligand for alpha-2-delta subunit of voltage –gated calcium channels in the central nervous system, which exhibits potent anticonvulsant, analgesic and anxiolytic activity. Although it shows analgesic efficacy against neuropathic pain. The aim of this study is to evaluate the analgesic efficacy of preemptive use of oral pregabalin after maxillofacial surgery.

Material and Methods:

The study was conducted on 56 patients reporting to the Department of Oral & Maxillofacial Surgery at The Oxford Dental College & Hospital, Bangalore for maxillofacial surgery under general anaesthesia. Patients were selected on the basis of the inclusion criteria after obtaining the Informed consent.Patients were randomly divided into two groups, the experimental group and the control group. The following treatments were administered Tab.pregabalin 150mg orally for experimental group and placebo orally for control group. All the medication was administered 1 hour before the induction of anaesthesia with little sip of water by a staff nurse who will not involve in the study. Anaesthesia technique was standardized in both the groups. After connecting the standard monitors patients was induced with pentazocaine 30mg IV and propofol titrated 2mg/kg to loss of consciousness. Nasal or orotracheal intubation was facilitated by vecuronium 0.08mg/kg. Anaesthesia was maintained with nitrous oxide in oxygen and isoflurane maintained at end-tidal concentration of 1-1.5%. At the end of surgery residual neuromuscular paralysis was reversed with neostigmine 0.05mg/kg and glycopyrolate 0.01mg/kg. after satisfactory recovery, the patient was extubated and shifted to the post anaesthesia care unit(PACU). The side effects such as headache, sedation anddepression was noted. Baseline assessment of pain intensity using visual analogue scale (1-10 scale) was made before medication(time t-0), pain intensity and pain relief was assessed at (0,4,8,12 &24 hours) after surgery, duration of pain relief and overall efficacy of drug

Results

A Comparative two group clinical study was carried out. A total of 56 patients who visited the Department of Oral and Maxillofacial Surgery, The Oxford Dental College and Hospital, Bangalore, for maxillofacial surgery under general anaesthesia were enrolled for the study. Randomization ensured that there were approximately 28 patients per treatment group. 36 patients were males (64.29%) and 20 females (35.71%) (Table & Graph 1). Samples are gender matched with P=0.78. Their age ranged from 18-40 years with mean age of 32.91±5.54. Samples were age matched with P=0.76. Majority of patients were in their third decade (Table & Graph 2). VAS scale for pain, pain relief, and duration of pain relief (Tables and Graphs 3-8), in the two treatment groups was statistically analysed and yielded a significant (p≤ 0.001) in this study. The overall assessment of analgesic efficacy compared between Group IV and Group OP showed a significance (p≤ 0.001) (Table & Graph 9). The results in this study showed that the analgesic efficacy of Tab.Pregabalin 150mg (Group PG) was superior to oral placebo (Group P).

Conclusion

In the current study we have confirmed our hypothesis that preemptive used of oral pregabalin 150mg are more reliably achieved superior analgesia than the oral placebo. We therefore suggest that oral preoperative single dose of pregabalin 150mg is an effective method for reducing post-operative pain and postoperative rescue analgesia requirement in patients undergoing maxillofacial surgery under general anaesthesia.