Author: Suzanne Novak, MD, PhD

This three-part blog will discuss the use of opioids for chronic pain management. Part I will discuss evidence and indications for use of opioids for chronic pain, and potential adverse events with use. Part II will discuss ongoing use of chronic opioid therapy (COT), and discuss when and how opioids should be discontinued. Part III will discuss medication alternatives to opioids for chronic pain.

The Role of Opioids in Chronic Pain Management–Part I

The use of opioids for chronic pain management is controversial, and their efficacy is not well supported by current research. In addition, there is evidence of serious potential harms with use. This blog will discuss the following.

  • Evidence for use of opioid therapy for chronic pain
  • When should COT be considered?
  • Potential adverse events with use

Opioids have an established role for treatment of acute pain, which can be defined as an expected physiologic experience to noxious stimuli, normally sudden in onset, and time limited (generally of a duration of 7 to 30 days). [1] Chronic pain is frequently considered that which lasts for longer than 3 months.  Causes of chronic pain can be varied, and range from those related to an injury, inflammation, neuropathic pain, or even unknown causes. It also differs from acute pain in that with development of chronicity, changes can occur in the central and peripheral nervous systems.[2]

Evidence for Use of Opioid Therapy for Chronic Pain

Since the mid-2000s, multiple authors have examined available research for evidence of use of opioid therapy for chronic pain. The overall consensus of these reviews is there is little to support the use of opioids for chronic pain, with some suggestion that opioid treatment may actually retard functional recovery. The most recent of these reviews, conducted for the Agency for Healthcare Research and Quality, and published in April 2020, found the following:2

  • Evidence for long-term effectiveness for COT is very limited.
  • There is increased risk of serious harms with use, and these appear to be dose dependent.
  • In short-term follow up (1 to < 6 months), evidence shows no difference between opioids versus nonopioid medications in improvement of multiple outcomes including pain, function, and/or mental health status.
  • Co-prescription of sedative hypnotic drugs such as benzodiazepines and gabapentinoids (gabapentin and pregabalin) may increase risk of death from overdose.

When Should COT be Considered?

Opioids are not recommended as a first-line treatment for any etiology of chronic pain, including low back pain (with or without associated compressive/neuropathic conditions such as radiculopathy or failed surgery syndrome). In particular, they are not recommended for long-term treatment of neuropathic pain (such as complex regional pain syndrome or peripheral neuropathy). If opioids are prescribed there should be evidence of failure of first-line pharmacologic treatment such as non-steroidal anti-inflammatories (NSAIDs), or other non-pharmacologic treatment options. [3] Long-term use should only be considered with caution. The most common indication for opioid use for chronic pain is for acute exacerbation of severe pain (“flares”) in a chronic scenario.

Potential Adverse Events with Use

Major adverse events of opioid use include physical dependence, opioid use disorder (addiction), and overdose with the potential of death.  Current literature suggests risk increases as dose increases, duration increases, and as opioids are taken with multiple drugs including benzodiazepines, anticonvulsants (such as gabapentin or pregabalin), muscle relaxants, antidepressants, and sleep aids (such as zolpidem).

Overdose risk also increases when patients use opioids at the same time as illicit drugs. Other associated harms include fatigue, somnolence, itching, sleep disturbance, those related to the gastrointestinal system (constipation, nausea, and delayed gastric emptying), and those related to the endocrine system (opioid-induced endocrinopathy with androgen deficiency). There appears to be increased risk of infection, and cardiac-related complications. There appears to be an overall increased risk of death from any cause, including those related to overdoses. 2,

Opioids appear to have a strong influence on the ability to perform work-related activity. Current literature suggests that opioids may impair mental and physical ability to perform potentially hazardous tasks such as driving or operating heavy machinery.[5] Persistent opioid use is associated with permanent disability,[6] and studies show delayed recovery with use.[7]

Summary

With little evidence for use, and major evidence of potential adverse events, Part II of this blog will help to outline how to handle the use of opioid treatment for chronic pain if this is elected.

[1] HHS (U.S. Department of Health and Human Services). National pain strategy: A comprehensive population health-level strategy for pain. 2016. Available at: https://www​.iprcc.nih​.gov/sites/default/files​/HHSNational_Pain_Strategy_508C.pdf. [Reference list]. Accessed April 26, 2020.

[2] National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Board on Health Care Services; Committee on Evidence-Based Clinical Practice Guidelines for Prescribing Opioids for Acute Pain. Framing Opioid Prescribing Guidelines for Acute Pain: Developing the Evidence. Washington (DC): National Academies Press (US); 2019 Dec 19.

[3] Foster NE, et al. Lancet Low Back Pain Series Working Group. Prevention and treatment of low back pain: evidence, challenges, and promising directions. Lancet. 2018 Jun 9;391(10137):2368-2383.

[4] Manchikanti L, et al. Responsible, Safe, and Effective Prescription of Opioids for Chronic Non-Cancer Pain: American Society of Interventional Pain Physicians (ASIPP) Guidelines. Pain Physician. 2017 Feb;20(2S): S3-S92.

[5] Chihuri S, Li G. Use of prescription opioids and motor vehicle crashes: A meta-analysis. Accid Anal Prev. 2017 Dec;109:123-131.

[6] O’Hara NN, Pollak AN, Welsh CJ, O’Hara LM, Kwok AK, Herman A, Slobogean GP. Factors Associated With Persistent Opioid Use Among Injured Workers’ Compensation Claimants. JAMA Netw Open. 2018 Oct 5;1(6):e184050

[7] Gross DP, Stephens B, Bhambhani Y, Haykowsky M, Bostick GP, Rashiq S. Opioid prescriptions in Canadian workers’ compensation claimants: prescription trends and associations between early prescription and future recovery. Spine (Phila Pa 1976). 2009 Mar 1;34(5):525-31.

Author

Dr. Novak is a board-certified anesthesiologist and had her PhD in Pharmacy Administration. She is president of Austin Outcomes Research, Inc., a healthcare consulting and utilization review firm with multiple national carriers and legal firms as clients. She is the lead author of the Pain Chapter of the ODG Treatment Guidelines and is a clinical assistant professor at the College of Pharmacy at the University of Texas at Austin where she is active in the Pharmacy Practice Division.

Read Part Two: Ongoing Use of COT and How Opioids Should be Discontinued

Read Part Three: Medication Alternatives to Opioids for Chronic Pain