Correlation of genetic variations with use of remifentanil as the analgesic during elective thyroid gland surgery

Genetic factors may alter the pharmacokinetic and pharmacodynamic properties of certain analgesic agents and therefore can modify individual clinical response to their administration. Although polymorphisms of enzymes responsible for the metabolism and transport of various drugs eventually affect their pharmacokinetics, other polymorphisms may also alter the pharmacodynamics of the particular drug. Patients undergoing elective thyroidectomy have different requirements in perioperative analgesia with short action opiate. In order to investigate the possible association of the response of these patients to remifentanil with the polymorphisms of SLC6A4 andABCB1 genes we will administer remifentanyl with Target Controlled Infusion technique in patients undergoing elective thyroidectomy. Preoperatively all patients will be evaluated with Hamilton anxiety scale rating test. The total remifentanyl requirements as well as the subjective postoperative pain will be associated with the polymorphisms of SLC6A4 andABCB1 genes.