New Techniques Get At Pain Where It Hurts
Theoretically, by using a facilitator to deliver anesthetic to people during surgery, a single shot of 1/1,000th of the usual dose could give several days of pain control after surgery, while avoiding side effects that could lengthen hospital stay. By using this technique with well-known drugs, "we could be optimistic about safety issues," Filler adds.
"This is a very flexible program to solve many different types of problems," says Filler. Using a pain medication on pain-sensitive nerves could relieve pain in conditions like shingles or diabetes, while injecting it into muscles could relieve muscle spasm in multiple sclerosis or spinal cord injury. Human studies are scheduled to begin in early 2002.
Drugs that might be effective in Alzheimer's disease or other brain diseases could be sprayed into the nose, where nerve cells lining the nose could carry them directly to the brain. Many drugs that were ineffective when given by mouth or into veins may prove to be useful once they reach their intended target.
Another approach to pain control is to transplant cells that make serotonin, a brain chemical thought to relieve pain, directly into the spinal cord. Acting as biological mini-pumps, they could deliver continuous pain relief while minimizing side effects.
"If this works in humans, it would be [as effective as] a kidney transplant for someone in kidney failure -- it would substitute for the loss of normal regulatory systems influencing pain," Bruce Nicholson, MD, director of pain management at Lehigh Valley Hospital in Allentown, Pa., tells WebMD. "This could be of great benefit for long-term pain control without medications," says Nicholson, who was not involved in the study.
In animals with spinal cord injuries, researchers at the University of Texas Medical Branch in Galveston and the Miami Project to Cure Paralysis found that these transplanted cells improved movement and decreased evidence of pain. However, there are many issues that must still be addressed before testing this approach in humans.
SynGenix, Ltd. of Cambridge, England, partly funded the axonal transport facilitator research. Filler is a co-founder, consultant, and significant shareholder in SynGenix, which holds the rights to ProVector, this axonal transport system.