Nerve blocks using local anesthetics, or numbing medicines similar to Novocain, are routinely performed by anesthesiologists to provide pain relief for patients undergoing surgery. Although techniques exist to provide several days of pain relief, they usually require special skills plus additional time and resources, and aren't always possible. Therefore, additional additives are commonly mixed with the local anesthetic or given intravenously (IV) to make a single injection nerve block last as long as possible.
One such additive is the steroid dexamethasone. Although several previous studies have suggested that it may make a nerve block last longer when given via IV, these studies relied on subjective endpoints (e.g., when the patient thought the nerve block wore off or when they first asked for pain medication) to determine how long the nerve block lasted.
A study conducted by researchers at Wake Forest Baptist Medical Center differed in that it used an objective measurement (pin-prick assessment every 2-hours). The investigators found that IV dexamethasone did not prolong the numbing shot. However, a higher dose of IV dexamethasone decreased the amount of pain medication a patient needed and extended the time before the first pain medicine was requested.