the Analgesic Duration of Dexmedetomidine Compared to Dexamethasone as Adjuncts to Single Shot Interscalene Block

Currently, the most commonly employed adjunct to peripheral nerve blockade is perineural dexamethasone. In general, at the doses used in regional anesthesia, dexamethasone has a minimal side effect profile. However, while it has been shown to increase duration of analgesia, there have been concerns regarding its neurotoxicity in animal studies. In addition, dexamethasone has the potential to cause hyperglycemia in patients with impaired glucose metabolism as well as perineal pain and pruritis when administered peripherally.

Dexmedetomidine is a highly selective alpha-2 agonist that is commonly used in patients undergoing anesthesia or requiring sedation in a non-operative setting. As a peripherally administered medication, it has both sedating and analgesic properties, as well as the added benefit of avoidance of respiratory depression. Although it can rarely produce cardiac depression at high doses, its side effect profile is otherwise minimal and is generally very well tolerated by most patients. When administered peripherally, dexmedetomidine has most commonly been associated with side effects such as hypotension, respiratory depression, and bradycardia - although all at significantly higher doses than planned in our study. The safe use of perineural dexmedetomidine together with local anesthetics has been described on numerous occasions. Nevertheless, although it has been shown to potentiate peripheral nerve blockade and prolong duration of analgesia in various studies , it remains rarely used as an adjunct to regional anesthesia.