Laryngoscopy and intubation are painful stimuli which invoke responses like tachycardia, hypertension and arrythmias. The hemodynamic stress response resulting from airway instrumentation are due to sympatho-adrenergic response caused by epi-pharyngeal and parapharyngeal stimulations which lead to rise in catecholamine level that increases blood pressure and heart rate.

          These Hemodynamic responses may be fatal in patients with coronary artery disease, hypertension, intracranial aneurysm, cerebrovascular disease and may cause MI, arrythmias, left ventricle failure and rupture of aneurysm.

        MELATONIN (N-acetyl-5-methoxytryptamine) is a endogenous sleep regulating hormone secreted by pineal gland. Exogenous administration of melatonin facilitates sleep and improves quality of sleep. It is different from benzodiazepines and their derivatives in that it produces natural sleep pattern and doesn’t lead impairment of cognitive functions. This drug has been mainly studied as sedative agent in intensive care unit and preoperatively as anxiolytic agent.

         PREGABALIN a gabapentinoid compound appears to produce an inhibitory modulation of neuronal excitability particularly neocortex, amygdala, hippocampus of CNS. It binds to the a₂d subunit of voltage dependent calcium channels and inhibits the channel. It possesses analgesic, anticonvulsant and anxiolytic activity by reduction of neurotransmitter glutamate, nor-adrenaline, serotonin, dopamine and substance P.