Researchers Create Long-Acting Local Anesthetic

TUESDAY, April 14 (HealthDay News) -- A new, slow-release injectable nerve block could be a long-lasting local anesthetic for the treatment of pain during and after surgery, U.S. researchers say.

The shot may also help patients with chronic pain, they add.

A team at Children's Hospital Boston created the anesthetic by packaging the potent painkiller saxitoxin into specially designed fat-based particles called liposomes. When tested in rats, this method proved effective in preventing pain and caused no damage to nerve or muscle cells.

The research was published online in this week's issue of 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," study senior author Dr. Daniel Kohane, of the division of critical care medicine in the department of anesthesiology, said in a Children's Hospital Boston news release. "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."

He and his colleagues are now improving the formulation to make it last even longer, while ensuring it's safe.

"It is conceivable we could have a formulation that is suitable for clinical trials [for humans] before too long," Kohane said.

"If these long-acting, low-toxicity formulations of local anesthetics are shown to be effective in humans, they could have a major impact on the treatment of acute and chronic pain. This slow-release technology may also have broader applications in drug delivery for the treatment of a variety of diseases," said Alison Cole, of the U.S. National Institute of General Medical Science, which partially funded the research.

More information

The American Academy of Family Physicians has more about pain control after surgery.