Next Decade Will Bring New Pain Management Options

NEW YORK—The next decade will bring advances in pain management as a direct result of research currently making its way from bench to bedside, said pain management expert Russell K. Portenoy, MD.

Researchers are elucidating the pathological changes in normal physiology that eventuate in chronic pain, and are evaluating new ways to modulate those changes using a variety of new and existing agents, according to Dr. Portenoy, chairman of the Department of Pain Medicine and Palliative Care, Beth Israel Medical Center, New York.

"When I got into the pain field, we basically had opioids, anti-inflammatory drugs, and maybe two adjuvant analgesics," Dr. Portenoy said at a media briefing held by the American Medical Association. "This adjuvant analgesic group now has about 70 different medications, and in the next 10 years, there will be an explosion of new agents coming on the market."

It is now recognized that a variety of available agents, including anticonvulsants, antiarrhythmics, antispasmodics, and most antidepressants, have pain-killing properties. In cancer patients, for example, antidepressants can ameliorate pain even if there is no evidence of a comorbid depressive disorder, Dr. Portenoy said.

Likewise, COX-2-specific inhibitors have revolutionized anti-inflammatory therapy, and botulinum toxin, brought on the market to treat problems with abnormal muscle tone, is now being used to treat headache, neck pain, and lower back pain.

Research is also suggesting that cannabinoid agents will be useful as analgesics. Other promising agents include nitric oxide inhibitors, N-methyl-D-asparate (NMDA) receptor antagonists, and compounds that interact with gamma-amino butyric acid (GABA) receptors. "All of these drugs are being developed, and at least some of them are likely to appear on the market within the next few years, greatly expanding even further this extraordinary armamentarium of pharmacologic agents for chronic pain," Dr. Portenoy said.

New Drug Delivery Methods

Current research also suggests new ways to improve drug delivery, either making administration more convenient or improving the therapeutic index such that the drug is more effective or has fewer side effects.

Iontopheresis (the use of constant direct low-voltage current to drive medications into and through the skin) will probably soon be available for opioid medications, Dr. Portenoy said.

Likewise, researchers are beginning to investigate delivery of analgesic drugs through the nose and oral mucous membranes. Rapidly dissolving tablets may be a way to get pain medication into the body as quickly as IV delivery. Inhalers now used to treat bronchospasm may be useful as well.

Further, he said, a great deal of research is documenting the feasibility of delivering pain medication via the spine. Implantation of infusion pumps for analgesic drug delivery is now common practice, but technological advances over the next decade will make these devices more sophisticated, smaller, easier to insert, and easier to change, Dr. Portenoy predicted.

"Essentially, chronic pain management today is a process of assessing a patient and deciding on a menu of approaches from a variety of different areas," Dr. Portenoy commented. "All of these areas are undergoing rapid research changes, potentially leading to more sophisticated, multimodality treatment strategies."