Comparative analysis of pretreatment with dexmedetomidine v/s ketamine to alleviate the degree of propofol injection pain

Propofol is an extensively  used I V anaesthetic agent for induction  as well as maintenance of anaesthesia. Propofol is known for its  rapid onset of action ,smooth induction and faster recovery without any residual  CNS effects  hence its an  induction drug of choice  for many anaesthesia forms and is also an agent of choice for daycare surgeries ,endoscopy, colonoscopy procedures . But the major drawback is the propofol injection pain which  occurs in 28 to 90 percentage of the patients and is often described by the  patients as severe or intolerable. To mitigate the PIP several pharmacological agents like lignocaine, fentanyl, remifentanil, ketamine, dexmedetomidine have been tried. Dexmedetomidine is a highly selective alpha2 adrenergic agonists exerts the antinociceptive effects by modulation of dorsal horn via alpha2b adrenoceptors and inhibition of the release of substance P. Ketamine is a noncompetitive NMDA receptor antagonist with local anaesthetic and systemic analgesia effect. It prevents sensitization of peripheral nociceptors and also has additional opioid receptor receptor activity contributing to pain relief. Although there has been individual studies on the effect of Dexmedetomidine and Ketamine on PIP, comparative studies on the effectiveness of these drugs in reducing PIP are limited necessitating this study.