Efficacy of drugs in regional anesthesia: a review

Abstract: Local anesthetics and opioids are the most commonly used drugs in regional anesthesia. Several other drugs are used as adjuvants in addition to local anesthetics. We will review the drugs currently used in regional anesthesia. In April 2009 we searched the PubMed database and found 143 articles related to the clinical use of drugs in regional anesthesia; we divided them into 3 major chapters: local anesthetics, opioids and adjuvants. Among local anesthetics, ropivacaine and levobupivacaine can be considered the drugs of choice in neuraxial and peripheral techniques because their toxicity is low even in large volume administration; mepivacaine can be considered the drug of choice in peripheral techniques when a shorter blockade is needed. Sufentanil is the opioid of choice in both neuraxial and peripheral techniques because it appears to improve the quality of anesthesia and to prolong sensory blockade in the postoperative period. Among the adjuvants to local anesthetics, clonidine is by far the most used drug in regional anesthesia; its yield in improving and prolonging the effects of local anesthetics is apparent in neuraxial techniques. Other drugs have been studied as adjuvants to local anesthetics but clinical evidence of their benefit is controversial in many cases and further trials are unquestionably warranted. In conclusion, since many different drugs are available for regional anesthesia, we must choose wisely the one that exhibits the best safety-efficacy profile and that suits the chosen technique and type of anesthesia/analgesia best.