Compound numbs pain 5X longer than lidocaine

"Having a longer lasting anesthetic reduces the dosage or number of doses needed, limiting the potential for adverse side effects," says George Kracke. (Credit: School of Veterinary Medicine and Science University of Nottingham, UK/Flickr)

A new compound offers longer-lasting pain relief with no serious side effects, and experts say it shows promise as an alternative to current anesthetics, including lidocaine.

“Because of its versatility and effectiveness at quickly numbing pain in targeted areas, lidocaine has been the gold standard in local anesthetics for more than 50 years,” says George Kracke, associate professor of anesthesiology and perioperative medicine at University of Missouri School of Medicine.

“While lidocaine is effective as a short-term painkiller, its effects wear off quickly. We developed a new compound that can quickly provide longer lasting relief. This type of painkiller could be beneficial in treating sports injuries or in joint replacement procedures.”

25 minutes of relief

Painkillers work by interfering with the nervous system’s transmission of nerve signals that the body perceives as pain. Lidocaine is used as an injectable pain reliever in minor surgical or dental procedures, or as a topical ointment or spray to relieve itching, burning, and pain from shingles, sunburns, jellyfish stings, and insect bites.

The new compound, called boronicaine, could potentially serve many of those same functions as an injectable or topical painkiller.

To develop the compound, M. Frederick Hawthorne, director of the International Institute of Nano and Molecular Medicine at the University of Missouri, synthesized boronicaine as a derivative of lidocaine. By changing aspects of the chemical structure of lidocaine, the new compound provided pain relief that lasted five times longer than lidocaine.

In pre-clinical, early stage studies, boronicaine provided about 25 minutes of relief, compared to about five minutes of pain relief with lidocaine.

Fewer side effects

“Although some conditions may warrant the use of a short-lasting painkiller, in many cases a longer lasting anesthetic is a better option,” Kracke says. “Having a longer lasting anesthetic reduces the dosage or number of doses needed, limiting the potential for adverse side effects.”

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While other types of painkillers can provide longer pain relief than lidocaine, they can cause heart toxicity, gastrointestinal issues, and other side effects. Preliminary findings show no toxicity in single-dose studies of boronicaine, though more studies are needed.

“Boronicaine could have distinct advantages over existing painkilling medications,” says Hawthorne, distinguished professor of chemistry and radiology. “We’re conducting more research into the side effects of the compound, but in time it could very well become a useful material to use as an anesthetic.”

The paper, presented at the Experimental Biology 2015 conference in Boston, is also published in the journal ChemMedChem.

The University of Missouri System Intellectual Property Fast Track Funding Program, the MU International Institute of Nano and Molecular Medicine, and the MU Department of Anesthesiology and Perioperative Medicine funded the work.

Source: University of Missouri