Surgery and anaesthesia is a stressful condition and are associated with stimulation of neuroendocrinal pathway, producing various hemodynamic effects, which may be harmful for the patient. Methods to decrease these effects include maintaining an adequate depth of anaesthesia to prevent these hemodynamic effects, or to give some pharmacological preparation to the patients, which will modify the response of anaesthetic drugs

Premedication is a part of pre-anaesthesia preparation which aims to prepare patients both physically and mentally for anaesthetic procedures. The main goal of pre-treatment is to eliminate anxiety. There are several classes of drugs used for the purposes of premedication, including sedatives, alpha-2 adrenergic agonists, anticholinergics, narcotics, antihistamines, antacids, and H2 antagonists 

Included in the sedative group are barbiturates, benzodiazepines, and butyrophenones. Midazolam belongs to benzodiazepine group, which is water soluble. It is short acting, widely used as an anxiolytic, sedative, and anaesthetic adjuvant, and has numerous advantages, such as a short elimination half-life, a significant anterograde amnesia, mild respiratory depression, and a relief of anxiety 

Dexmedetomidine is a highly selective alpha 2 adrenergic receptor agonist and possesses the potential benefit of sedation, sympatholysis, analgesia, and cardiovascular stability, Its hemodynamic effects are predictable and dose dependent. Dexmeditomidine, at clinically effective dosages, does not depress respiration, and therefore does not interfere with extubation 

Laparoscopic surgery is a modern surgical technique involving insufflation of gas (usually CO2) into the peritoneal cavity under pressure to separate organs from abdominal cavity. Laparoscopic cholecystectomy has revolutionized gall bladder surgeries and it has now become the gold standard for the treatment cholelithiasis