New Techniques Get At Pain Where It Hurts
"Because it's released directly to where it's needed, you can use as little as 1/10,000th of the dose that would be needed by other routes," Filler says.
In animals, Filler showed that a single injection into a painful area of 1/300th of the usual dosage of a drug bound to the facilitator reduced evidence of pain by 50%, with pain relief lasting up to four days. Yet the drug alone, without the facilitator, had no effect on pain.
"This is not only a clever idea but a well-done study," John A. Jane Sr., MD, PhD, tells WebMD. "In humans, this approach might eventually be applicable to [painful nerve conditions] or cancer pain." Jane, who is professor and chair of neurosurgery at the University of Virginia Health System in Charlottesville, was not involved in the study.
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.