NIDA Notes: How important is pain as a public health issue?
David Thomas: Hugely important. The Institute of Medicine (IOM) estimates that over 100 million adults in the United States experience chronic pain. The costs to society, counting both medical expenses and lost productivity, are estimated by IOM to be more than a half-trillion dollars per year. Moreover, the prevalence of chronic pain is expected to rise in the near future as the incidence of diabetes, cardiovascular disorders, arthritis, and cancer increases in the aging U.S. population.
NN: How are the problems of chronic pain and prescription opioid abuse related?
DT: They are intertwined. The current urgency in addressing these problems relates to changed prescribing practices and other factors that have resulted in the near tripling of opioid prescriptions—to 219 million—during the past two decades. There are just a lot of opioids out there available for people to use without a prescription or in excess of the prescribed amount.
In parallel, deaths caused by prescription opioids have also increased. A recent report by the Centers for Disease Control and Prevention pointed out that today, many more people are dying from unintentional prescription painkiller overdoses than in the past. Overdoses of prescription opioids now account for more deaths annually than overdoses of cocaine and heroin combined.
NN: What is NIDA doing to address these problems?
DT: NIDA supports efforts to generate a medication that will provide effective pain relief but without the potential for abuse and addiction. NIDA-funded scientists are pursuing several lines of investigation to bring this goal closer. One of the most promising is separating out the mechanisms that produce opioids’ good effects from those that produce their bad effects. Such knowledge could open the way to medications that activate the good mechanisms and suppress the bad.
For example, we have known for a long time that opioids produce analgesia by stimulating receptors on neurons. Recently, however, Dr. Linda Watkins at the University of Colorado, Boulder, and colleagues have shown that, in contrast, opioids produce many of their negative effects by stimulating receptors on a different type of cells, called glia. This suggests that a medication that stimulates opioid receptors while blocking glial receptors might suppress pain without causing those negative effects. Dr. Watkins’ group is now investigating how glia produce the undesirable side effects (“Basic Science Discoveries Yield Novel Approaches to Analgesia”) and looking for ways to block the responsible glial receptors.
Another promising object of study is a chemical called resiniferatoxin (RTX), which selectively kills overactive pain fibers in the spinal cord. NIDA helped to obtain clearance from the Food and Drug Administration (FDA) to begin clinical studies of RTX. Initial trials at the National Institutes of Health (NIH) Clinical Center have shown remarkable efficacy in the reduction of severe cancer pain. Incidentally, RTX occurs in a type of cactus and is related to capsaicin, which is the ingredient that makes hot peppers hot.
Although researchers have yet to determine how, there is evidence to indicate that drug abuse causes addiction by modulating not only the brain’s pleasure centers, but also its pain systems. For example, the strongest known analgesics are the ones that have the highest abuse potential, and many illicit addictive drugs also have analgesic properties. Thus, NIDA supports research seeking to understand how brain reward-processing and pain-processing pathways, alone or together, contribute to addiction. We hope that the results will facilitate the development of new treatments for pain and perhaps therapies for prescription opioid abuse.
NN: What is the NIH Pain Consortium?
DT: NIH established the NIH Pain Consortium in 1996 to promote and coordinate pain research throughout all the Institutes and Centers. NIDA Director Dr. Nora D. Volkow is on the Consortium’s five-member Executive Committee.
NN: What is the Centers of Excellence program?
NIDA is leading a major Consortium initiative to foster the creation of NIH Centers of Excellence in Pain Education. The impetus for the project emerged from a 2010 workshop that NIDA’s Prescription Opioids and Pain Workgroup convened in collaboration with the Consortium. The workshop participants recognized that health care professionals are at the fulcrum of two health crises—inadequate treatment of chronic pain and misuse of prescription opiates. Doctors, dentists, nurses, pharmacists, and other providers must be aware of, and also educate patients on, therapeutic options, potential problems associated with those therapies, and signs of abuse and addiction. However, the workshop consensus was that health professionals’ training typically does not equip them to meet these challenges.
To help remedy this situation, the workshop participants suggested that NIH could facilitate improved pain education by supporting what they called Pain Champions—individuals at various teaching institutions who see the need for and are willing to take the necessary steps to establish new courses in pain management. Accordingly, in late 2011, the Consortium released a request to medical, dental, nursing, and pharmacy schools across the Nation for proposals to become Centers of Excellence. There was a huge response: NIH received 56 applications, representing 197 institutions, and selected 12 schools:
- Harvard School of Dental Medicine, Boston
- Johns Hopkins University
- Southern Illinois University, Edwardsville
- Thomas Jefferson University School of Medicine, Philadelphia
- University of Alabama at Birmingham
- University of California, San Francisco
- University of Maryland, Baltimore
- University of New Mexico, Albuquerque
- University of Pennsylvania Perelman School of Medicine, Philadelphia
- University of Pittsburgh
- University of Rochester, New York
- University of Washington, Seattle
This year and next, these Centers will work with staff across NIH to develop curricula on pain that will be used in their courses. After testing and refining, they will disseminate the materials to other academic institutions and make these tools available on the Consortium’s Web site.
I head the NIH team overseeing this project, and other NIDA staff play key roles:
- Dr. Richard Denisco of the Division of Epidemiology, Services, and Prevention Research serves as the topic expert on pain and pain treatment.
- Ms. Carol Krause, Chief of the Public Information and Liaison Branch, serves as the topic expert on education.
- Dr. Redonna Chandler, Chief of the Services Research Branch in the Division of Epidemiology, Services, and Prevention Research, provides project support.
- Dr. Denise Pintello, Special Assistant to the Deputy Director, also provides project support.
NN: What do you think will be the potential impact of the program?
DT: Even a small improvement in pain education could have a huge effect, as each health care professional works with many patients. Today, nationwide, there are only about 4,000 professionals who specialize in pain medicine. To reach more patients, it makes sense to improve the pain education of medical professionals who do not specialize in pain treatment.
This is consistent as well with the thinking of FDA, which recently stated that prescriber education is key to curtailing prescription opioid abuse. The Institute of Medicine also recommends changing the education of health professionals in a recently issued report on how the health care system can better address chronic pain.
NN: What is your hope for pain treatment 10 years from now?
DT: I hope we will have pain treatments that are more effective and that have little abuse liability. My colleagues and I envision a future where health care professionals will feel confident in their ability to effectively alleviate the suffering of their patients without risk of painkiller abuse, and patients will have confidence that their pain will be treated successfully without exposing them to addiction risk.