Comparison of Oral Pregabalin and Clonidine Premedication in Attenuating Pressor Response to Laryngoscopy and Intubation: A Prospective Interventional Study

Introduction: Laryngoscopy and intubation during the induction of general anaesthesia can lead to sympathetic system-mediated haemodynamic pressor response, which, if exaggerated, may lead to hazardous complications like myocardial ischaemia, arrhythmias, and cerebral haemorrhage. Although several pharmacological and technical methods are available to attenuate this stress response, the search for an ideal agent continues. Aim: To compare the effects of orally administered clonidine and pregabalin in attenuating the haemodynamic pressor response to airway instrumentation during the administration of general anaesthesia. Materials and Methods: The present prospective interventional study was conducted between June 2020 and July 2021 at Government Medical College, Kozhikode, Kerala, India. A total of 176 American Society of Anaesthesiologists (ASA) Physical Status I patients aged between 18 and 65 years were included. Patients were categorised into two groups: Group P received oral pregabalin 150 mg and Group C received oral clonidine 200 mcg, 60 minutes before the induction of GA. Haemodynamic parameters {Heart Rate (HR), Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), Mean Arterial Pressure (MAP)} and Ramsay sedation scores were recorded at predefined intervals. Statistical analysis was performed using International Business Machine (IBM) Statistical Packages of Social Sciences (SPSS) software, with data expressed as mean±Standard Deviation (SD). Differences between groups were assessed using the Chisquare test, independent samples t-test, and Mann-Whitney U test, with a p-value of <0.05 considered statistically significant. Results: Demographic variables and baseline parameters were comparable between the groups. A statistically significant reduction in HR was observed in the clonidine group compared to the pregabalin group (p<0.05) at multiple time intervals post-drug administration. SBP, DBP, and MAP values showed reductions in both groups, with no significant intergroup differences (p>0.05). A higher incidence of bradycardia and hypotension was noted in the clonidine group (p<0.05). Sedation scores, compared using the Mann-Whitney U test, revealed significantly higher sedation in the pregabalin group at one hour after drug administration and 15 minutes after extubation. Conclusion: Both clonidine 200 mcg and pregabalin 150 mg, when administered orally one hour before the induction of anaesthesia, are effective in attenuating the haemodynamic pressor response. Clonidine is superior to pregabalin in reducing tachycardia; however, clonidine carries a higher risk of bradycardia and hypotension, whereas pregabalin results in greater postoperative sedation.