By Julie Black, R.Ph., Product Director, Coventry Workers’ Comp
Treatment of pain is estimated to cost the United States approximately $635 billion per year. 1 Prescription medications are a significant portion of that expense with narcotics now responsible for approximately 35% of workers’ compensation claim prescription spending. Costs continue to rise as a result of both new, more expensive medications, and ever increasing doses of narcotics prescribed to injured workers. Until recently, tolerance, dependence, and addiction were the only concerns for clinicians as doses of narcotics continued to increase. In May 2012, the US Pharmacist Journal brought to light a new phenomenon: how can this patient consistently require increases in narcotic doses without exhibiting any pain relief? The answer…opioid-induced hyperalgesia (OIH).
The term, opioid-induced hyperalgesia (OIH), was coined for situations where the narcotic itself increases the level of pain that patients experience. Almost inexplicably, the medication that is intended to relieve the pain is actually worsening the pain, and thus requiring escalating doses of narcotics for pain relief. As narcotic doses increase, so do significant adverse events such as central nervous system depression and death. According to the Agency Medical Directors Group (AMDG) in the State of Washington, the 2010 Guidelines state that narcotic prescriptions above 100 mg Morphine Equivalent Dose (MED) per day result in a 9-fold increase in risk of overdose with 12% of overdoses being fatal.2 By extrapolation, it is clear that OIH is more than just a new diagnosis, it is likely responsible for an unmeasured number of unintentional overdoses and accidental deaths.
In order to prevent narcotic doses from rising to dangerous levels, it is important to recognize the common signs of OIH (list below).1
Common Characteristics of Opioid-Induced Hyperalgesia
- Worsening pain over time in spite of, and because of, increases in opioid dose
- Nociceptive sensitization
- Area of pain more diffuse
- Pain of lesser quality and harder to pinpoint
The cause of OIH is currently under investigation. The leading theory continues to be excitation of nerves through chemical pathways by certain narcotics. Research has demonstrated that some narcotics may have a higher propensity to cause OIH. The “phenanthrene opioid” class which includes codeine, hydrocodone, oxycodone, morphine, oxymorphone, and hydromorphone appears to have a stronger association to OIH. In patients who experience escalating doses due to increased pain, switching to a non-phenanthrene opioid such as meperidine or tramadol often leads to adequate pain relief.
Considerations for Chronic Pain Managment
Although not yet well understood, OIH has the potential to change the way clinicians diagnose and treat chronic pain. To date, it has been assumed that patients require increased doses of narcotics because their bodies have become tolerant and a higher dose is needed to adequately treat the pain. However, the definition of tolerance states that pain relief did occur at the lower dose and sometime later, a higher dose was necessary. In the case of OIH, it is not clear if pain is ever adequately addressed or if pain relief occurs initially, but is lost as treatment continues.
The potential for injured workers to experience OIH is elevated due to the rampant use of narcotics to treat various chronic pain diagnoses. Injured workers whose narcotic doses continue to escalate many years after the injury without any exacerbating factors should be identified and referred for OIH evaluation by the pharmacy benefit manager or clinical case manager. It is likely that OIH is responsible for a significant percentage of the dollars spent within the workers’ compensation system as the medication costs, side-effect management, and addiction treatment drive up the overall cost of the claim. The ability to identify and treat OIH appropriately will lead to better clinical outcomes and a decreased financial burden on the workers’ compensation system.
About Julie Black
Julie Black is a registered pharmacist in Arizona, California, and Missouri. She is responsible for the development of new and enhanced clinical pharmacy programs for First Script, the Coventry Workers’ Comp Services Pharmacy Benefit Management Program. Julie’s 6 years with Coventry include her previous management of the clinical pharmacy operations team. Julie has worked for a group health PBM, several chain settings, a closed staff long-term care pharmacy, and has performed both adverse event reporting and patient education programs throughout the pharmaceutical industry. Julie received her Bachelor of Science in Pharmacy from the University of Missouri at Kansas City.
About Coventry Workers’ Comp Services
Coventry Workers’ Comp Services, a division of Coventry Health Care, Inc. (NYSE: CVH), is the leading provider of cost and care management solutions for property and casualty insurance carriers, (workers’ compensation and auto insurers), third-party administrators and self-insured employers. We design best-in-class products and services to help our partners restore the health and productivity of injured workers and insureds as quickly and as cost effectively as possible. We accomplish this by developing and maintaining consultative, trusting partnerships with our clients and stakeholders, built on a foundation of innovative and customized solutions that support the claims management process.
1 Opioid-Induced Hyperalgesia: Retrieved from the Medscape website on 8/17/12 at http://www.medscape.com/viewarticle/765277.
2 Interagency Guideline on Opioid Dosing for Chronic Non-cancer Pain; Retrieved from the Agency Medical Directors’ Group website on 8/17/12 at http://www.agencymeddirectors.wa.gov/opioiddosing.asp.