Long-lasting Nerve Block Could Change Pain Management

April 14th, 2009 in Medicine & Health / Research

(PhysOrg.com) — Harvard researchers at Children’s Hospital Boston have developed a slow-release anesthetic drug-delivery system that could potentially revolutionize treatment of pain during and after surgery, and may also have a large impact on chronic pain management.

In work funded by the National Institutes of Health (NIH), they used specially designed fat-based particles called liposomes to package saxitoxin, a potent anesthetic, and produced long-lasting local anesthesia in rats without apparent toxicity to nerve or muscle cells.

The research will be published online during the week of April 13-17 by the Proceedings of the National Academy of Sciences.

“The idea was to have a single injection that could produce a nerve block lasting days, weeks, maybe even months,” explains Daniel Kohane of the Division of Critical Care Medicine in the Department of Anesthesiology at Children’s, the report’s senior author, and associate professor of anesthesia at Harvard Medical School. “It would be useful for conditions like chronic pain where, rather than use narcotics, which are systemic and pose a risk of addiction, you could just put that piece of the body to sleep, so to speak.”

Previous attempts to develop slow-release anesthetics have not been successful because of the tendency for conventional anesthetics to cause toxicity to surrounding tissue. Indeed, drug-packaging materials have themselves been shown to cause tissue damage. Now, Kohane and colleagues report that if saxitoxin is packaged within liposomes, it is able to block nerve transmission of pain without causing significant nerve or muscle damage. More…