Dexmedetomidine is a potent and highly selective alfa2-adrenoreceptor agonist. It has sedative-hypnotic, anxiolytic, analgesic, anesthetic and sympatholytic effects. Intra-articular dexmedetomidine was used in several studies to enhance postoperative analgesia after knee arthroscopy with an increased time to first analgesic request and a decreased need for postoperative analgesia Neostigmine is an anticholinesterase and also has antinociceptive effects when administered intrathecally or peripherally.