Effectiveness and Safety of Epinephrine as an Adjuvant to Local Anesthetics in Regional Anesthesia: A Systematic Review

Abstract

Epinephrine has long been used as an adjuvant in local anesthesia to prolong block duration and improve analgesic quality. Its primary mechanism is related to its vasoconstrictive effect, which reduces the systemic absorption of local anesthetics. However, its clinical effectiveness and safety profile remain subjects of debate in the literature. This study aimed to evaluate the effectiveness and safety of epinephrine as an adjuvant in regional anesthesia techniques. A systematic review was conducted following the PRISMA 2020 guidelines through searches of PubMed and other relevant sources. Inclusion criteria consisted of randomized controlled trials and controlled studies comparing the use of local anesthetics with and without epinephrine. The primary outcomes analyzed included the duration of sensory block/analgesia and the incidence of cardiovascular and neurological adverse effects. The results showed that the addition of epinephrine generally prolonged the duration of sensory block and analgesia by approximately 30–60 minutes in several neuraxial and locoregional anesthesia techniques. Reported adverse effects were generally mild and transient, mainly related to hemodynamic changes. However, data regarding cardiovascular and neurological risks remain limited and variable across studies. In conclusion, epinephrine is an effective adjuvant for improving the duration and quality of local anesthesia in regional anesthesia, with a relatively favorable safety profile when used at appropriate doses. Nevertheless, further studies are required to clarify cardiovascular and neurological risks more comprehensively