The cardiovascular response to ketamine: the effects of clonidine and lignocaine

Abstract

The effectiveness of clonidine or lignocaine in reducing the cardiostimulatory effects of ketamine was studied. A double-blind, randomized design was used in three groups of 20 patients each, of ASA grade 1 or 2 presenting for minor elective surgery. The clonidine group received 0.3 mg clonidine orally with the premedication while the lignocaine group received 1.5 mg.kg-1 lignocaine prior to induction. The third group formed the controls. All patients were induced with 2 mg.kg-1 ketamine intravenously. The systolic blood pressure in the clonidine group was significantly lower than that of both the control and lignocaine groups throughout the study (P < 0.05). It was concluded that clonidine was effective in reducing the hypertensive response to ketamine, whereas lignocaine had no effect.

Increase in Blood Pressure by Local Injection of Ketamine into the Amygdala in Rats

“…Since ketamine antagonizes NMDA receptors, but not AMPA receptors, postsynaptic neurons may be activated through APMA receptors [29][30][31][32][33] . On the other hand, ketamine acts as α and β adrenergic receptor agonists, activating the sympathetic nervous system, and resulting in bronchodilation, tachycardia, and pressor action 13,34,35) . In addition, ketamine inhibits catecholamine transporter to increase free catecholamines in the synaptic space 12,36,37) .…”

A Comparative Study Of Intravenous Clonidine And Intravenous Dexmedetomidine Premedication On Cardiovascular Response To Ketamine Anesthesia In Patients Undergoing Dilatation & Curettage.

“…Doak GJ, Duke PC [15] studied effect of oral clonidine premedication in attenuating the haemodynamic effects associated with ketamine induction. Munro HM, Sleigh JW, Paxton LD [16] studied the effectiveness of clonidine or lignocaine in reducing the cardiostimulatory effects of ketamine. Handa F,Tanaka M, Nishikawa T, Toyooka H [17] conducted a study to determine the effects of oral clonidine premedication on haemodynamic changes during the entire course of ketamine anaesthesia and concluded that oral clonidine 2.5 microgram/kg and 5 microgram/kg attenuate cardiostimulatory effects associated with ketamine induction.…”