Oral clonidine and gabapentin suppress pressor response: A prospective, randomized, double blind study

Pressor response is a part of stress response caused by reflex sympathetic discharge due to direct laryngoscopy and tracheal intubation resulting in tachycardia, hypertension and arrhythmias. Both clonidine, and gabapentin administered orally can effectively blunt this detrimental hemodynamic response.

To study the effect of oral clonidine to blunt the pressor response to direct laryngoscopy and to compare it with oral gabapentin. To observe for postoperative sedation and side effects if any.

Sixty patients of American Society of Anaesthesiologist Grade I and II scheduled for surgery under general anesthesia were considered in this prospective randomized double-blind study. They were randomly allocated into two groups of 30 each using computerized randomization.

Group A was given oral clonidine 5 μg/kg and Group B was given oral gabapentin 800 mg. Both the drugs were given 90 min prior to surgery. Heart rate (HR) and blood pressure were monitored at baseline, 0, 1, 3, 5, 10, 15, and 30(th) min of laryngoscopy. Sedation was monitored by Ramsay Sedation Scale score and side effects were noted.

HR decreased in both groups at 0 and 1 min, increased at 3(rd) min and gradually decreased by 30(th) min. Statistically, significant difference was found between two groups at 1, 3, 5, 10, and 15(th) min (P < 0.05). Though there was no significant difference in systolic blood pressure, diastolic blood pressure and mean arterial pressure between the two groups, there was no rise in these parameters. Gabapentin produced more sedation than clonidine postoperatively, and few side effects were noted.

Both oral clonidine and gabapentin are effective in obtunding pressor response to direct laryngoscopy, clonidine being better in terms of controlling HR. Gabapentin produces more postoperative sedation than clonidine.