Content courtesy of Ivanhoe. For more, visit ivanhoe.com.

The annual cost of chronic pain in the U.S. is estimated to be $100 billion. Nearly 5 million people go to their doctors for relief from the condition, but meds can wear off, and patients run the risk of addiction. Researchers are working on a new approach to chronic pain in the form of an injection that could ease the discomfort for days

For Meri Kennedy, cleaning isn't just tedious -- it's painful. Every ache is a reminder of a life-long battle with chronic pain, the result of a long list of health complications.

"Fractured ribs, polyps in my vocal chord, breast cancer, fractured hip, injury to my knee," Kennedy said.

Kennedy relies on pain meds to get through the day.

"I am afraid I can get addicted to the pain meds," she said.

Soon, people like Kennedy may be able to stop the pill popping and get one injection that blocks pain for days.

"We have developed some liposomes which, when injected either into the tissue or a nerve area, can numb the area for about a week," Dan Kohane, M.D., Ph.D., Senior Associate of Critical Care at Children's Hospital Boston, told Ivanhoe.

Liposomes are specially designed fat-based particles that hold pain meds.

"When injected, liposomes just sit there and let the drugs leave," Dr. Kohane explained.

The liposomes slowly release a potent anesthetic over time. In animal studies, the technique blocked nerves without damaging surrounding cells or muscles.

"The main advantages of this type of formulation over taking a narcotic, for example, to the best of our knowledge these have no addictive potential but can treat the pain," Dr. Kohane said.

"I would welcome it, definitely," Kennedy said.

One shot … days of relief. For chronic pain sufferers, it could turn the chores of daily life into much more pleasant experiences.

The anesthetic used in the study is a toxin naturally found in certain bacteria and pufferfish.