Most local anesthetics in current use act quickly but briefly, with effects fading within eight to twelve hours and rarely exceeding a day. That short window can be a problem for managing pain through the full recovery period after surgery or injury.
Researchers at Boston Children's Hospital report a slow-release injectable formulation that extends that duration dramatically. In their work, the system achieved anesthetic nerve-block effects lasting two to three weeks from a single injection.
Because only one source was available, no independent or corroborating details are included here. The finding nonetheless points toward a longer-acting option for pain management that could reduce the need for repeat dosing or continuous delivery.