Why is this happening? The main reason is that to kill pain in one part of the body, you have to take a drug that affects the entire body. And this can be risky. Because they can have serious side effects, doctors are reluctant to prescribe high doses of morphine and other powerful pain killers.
Many people with chronic pain from diseases such as arthritis have a related problem. They may feel pain on a daily basis. But if they take enough medicine to take care of that pain and they do it every day for months or even years, they may cause liver or other damage.
A recent study by UCLA and Cambridge University, England, however, suggests that here may soon be an answer to this dilemma. At the November 8 Society for Neuroscience conference in New Orleans, La., researchers from these institutions reported a revolutionary advance in pain medicine that promises to deliver painkilling drugs exclusively to the affected area of the body. This would mean better pain relief with smaller doses and fewer side effects.
...[T]o kill pain in one part of the body, you have to take a drug that affects the entire body. And this can be risky.
Current methods of pain treatment involve delivering painkillers into the blood stream. The pain medication then travels throughout a patient's system, affecting areas of the body far removed from their target.
Experimenting on animals using a method called "axonal transport," UCLA neurosurgeon Aaron Filler and his colleagues were able to deliver a pain drug to a specific part of the body using nerves as a conduit, instead of the bloodstream.
TheDoctor's Peter Barland, M.D., comments that "the idea of local pain control is certainly not new, since all nerve blocks are based on this principle. However, if drugs can be delivered to a specific part of the body via the nerves that connect that area to the spinal cord — and if this can be done without damaging those nerves — then I would see this as a major advance in pain control."
Filler says that with this new method of delivering pain medication, one shot given during surgery could kill the pain that a patient would normally feel for several days afterward. The painkillers would go only to the nerves involved in the surgery, eliminating common side effects of traditional pain treatment such as nausea, drowsiness and impaired breathing.
"This very complex design achieves something that, previously, was not thought possible," Filler said. "The way it works makes this the first truly 21st-century medication. These results are expected to lead to dozens of new medications that will solve difficult drug delivery problems in the treatment of conditions as varied as stroke, Alzheimer's disease, shingles and herpes."
Offering a caution, however, Dr. Barland points out that this discovery may prove more valuable in dealing with short-term pain than with chronic pain. "The origin of the pain from most chronic illness," he says, "is not usually limited to a specific part of the body and therefore might not be amenable to this type of therapy. It would also be important to know whether giving long-term, repeated injections of this type of analgesic to those with chronic pain might actually do some damage to the nervous system."
Reviewed by Peter Barland, M.D.