Analgesic effect of intranasal dexmedetomidine in third molar surgery under local anaesthesia

Abstract

Dexmedetomidine is an alpha 2 agonist. Activation of central alpha 2-adrenoreceptors in the locus ceruleus is responsible for both analgesic and sedative effects. However, its analgesic effect is controversial in clinical practice. We aim to evaluate analgesic effect of intranasal dexmedetomidine when it was used for conscious sedation in unilateral third molar surgery under local anaesthesia. After IRB approval, 60 patients scheduled to have unilateral third molar surgery under local anaesthesia with conscious sedation were recruited into this double blind randomized control trial. They were randomly allocated to receive either intranasal dexmedetomidine 1 μg/kg (group D) or normal saline as placebo (group P) 45 minutes before surgery. Patient controlled sedation (PCS) with propofol was provided as rescue sedative. Pain on administration of dexmedetomidine, cannulation and local anaesthetic infiltration were evaluated. Postoperative pain scores as numerical rate scale (NRS) up to postoperative 72nd hour, adverse events, time to first analgesic, analgesic consumption and global pain satisfaction were also explored. After administration of intranasal dexmedetomidine, group D patients were more sedated before surgery (p<0.05) and used less rescue PCS propofol (p=0.003). No significant difference in pain on administration of dexmedetomidine, cannulation and local anaesthetic infiltration was found. Postoperative median NRS pain scores at specific time point were similar during the whole study period. However, the areas under curves (AUC) for NRS scores of postoperative resting pain from 1 to 12 hours was significantly lower (p=0.017) for group D. Incidence of side effects and global pain satisfaction between 2 groups were similar. Intranasal dexmedetomidine appears to offer better postoperative analgesic effect when it was used for conscious sedation in unilateral third molar surgery under local anaesthesia. No increase in postoperative adverse event was found.