Table 4.

Reported Adjunctive Agents for Regional Anesthesia *

Class	Agents
Nucleoside	Adenosine
Alpha2-adrenergic agonists	Clonidine; dexmedetomidine
Adrenergic agonist	Epinephrine
Anti-inflammatory agents	Parecoxib; lornoxicam
Opioids	Buprenorphine; butorphanol; fentanyl; hydromorphone; morphine; sufentanil; tramadol
Corticosteroids	Dexamethasone
Benzodiazepine	Midazolam
NMDA antagonists	Ketamine; magnesium
Cholinesterase inhibitor	Neostigmine

NMDA, N-methyl-D-aspartate

* Many of these medications are not approved for use in regional anesthesia techniques and their long-term safety has not been fully studied.