Tactical approaches to pharmacological enhancement of regional blocks: a review of the role of adjuvants

Abstract

Regional anesthesia has gained recognition in recent years as a promising field in anesthesiology, allowing a substantial reduction in perioperative opioid consumption and, consequently, decreasing the incidence of opioid‑related complications. The main limitation of this approach is the relatively short duration of nerve blockade. Considerable attention has been paid to pharmacological methods for prolonging sensory block, which can be achieved using adjuvants – drugs that enhance the effect of local anesthetics. This area is highly popular in contemporary international research. At present, five key groups of adjuvants have been described: α‑adrenergic agonists (epinephrine), α2‑agonists (dexmedetomidine, clonidine), glucocorticoids (dexamethasone), opioid analgesics (morphine, tramadol, fentanyl), and other agents (ketamine, magnesium sulfate, nonsteroidal anti‑inflammatory drugs [NSAIDs], pregabalin). The objective of this review is to analyze and systematize available data on the use of adjuvants for prolongation of regional nerve blocks.