Epidemiological context

The USA is in the midst of a decades-long, devastating opioid epidemic. More than 564 000 people died from opioid overdose from 1999 to 2020.1 The number of national opioid overdose deaths has been rising over the past 20 years, most recently rising from 46 802 opioid deaths in 2018 to 68 630 in 2020.1 In 2019, 10.1 million people aged 12 years and older misused opioids during that year.2 In 2018, the rate of opioid-related hospital stays in the USA was 286.1 per 100 000 people.3 Opioid users also have increased rates of emergency department visits and hospitalisations, with healthcare utilisations having increased substantially in recent decades.4 Three million people in the USA and 16 million people worldwide currently or previously suffered from opioid use disorder (OUD).5

OUD is defined by the American Psychiatric Association Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition as a desire to obtain and use opioids despite personal, social and professional consequences.6 An individual suffering from OUD experiences an overpowering need to use opioids, increased opioid tolerance and withdrawal symptoms if opioid use is stopped.5 Long-term use of opioids also results in dependence, which means that if the person were to stop taking, he/she would experience withdrawal symptoms such as nausea, vomiting, diarrhoea, abdominal cramps, anxiety, sweating, lacrimation, rhinorrhoea, muscle spasms/tension, aches/pains, irritability, insomnia and more.7 8

Over the past decade, fentanyl and other highly potent synthetic opioids have replaced heroin as the dominant opioid used illicitly.9 10 Besides overdose, there are many adverse effects of long-term opioid use. Opioids can negatively affect many body systems such as gastrointestinal, musculoskeletal, respiratory, cardiovascular, immune, endocrine and central nervous systems.11

Certain groups of people are more likely to use opioids and develop a use disorder than others. People with increased rates of OUD are non-Hispanic white people, men, 18–25-year olds, those who make less than $20 000 per year and those who are uninsured.12 In contrast, opioid overdoses are the highest among black and indigenous populations, highlighting racial inequities in accessing healthcare and substance use disorder treatment services.13 Factors such as level of education, housing stability and employment status have also been found to have a significant association with the frequency of opioid use.14 It is also known that people with pre-existing mental illness are more likely to initiate opioid use and become dependent on opioids, as drug use may relieve symptoms of the mental illness.15

Acute pain in individuals with OUD

Acute pain is defined as a physiological response to an adverse stimulus associated with surgery, trauma or acute illness.16 Patients with OUD are at high risk for transmissible and non-transmissible infections, as well as acute traumatic injuries, all of which can cause acute and extreme pain.17 Unlike the general population, there are additional challenges that come with treating acute pain in individuals with opioid dependence or use disorder. One challenge is opioid-induced hyperalgesia in which patients taking long-term opioids have an increased sensitivity to pain and an extreme pain response out of proportion to opioid-naive patients.18 Tolerance presents another challenge in treating acute pain in this patient population. Opioids are often used for treating severe acute pain, but the standard doses of opioids that would be used for an opioid-naive patient will not work effectively in an opioid-tolerant person.19 Another challenge is the symptoms of withdrawal. Opioid-dependent patients being treated for acute pain are at risk of withdrawal symptoms if opioid substitution therapy is not initiated promptly. This can happen if there are long wait times or if the medical provider refuses to prescribe opioids to treat the patient’s pain.20 Withdrawal symptoms cause additional suffering to the patient who is already experiencing acute pain. Lastly, a challenge that opioid users face when accessing any type of healthcare is the stigma from healthcare workers. It is well known that opioid users can face discrimination and receive suboptimal care in a healthcare setting due to stigma against drug use.21–24 Many healthcare providers prefer not to work with substance users who experience pain because they find this work challenging and unsatisfactory.25

Rationale for this scoping review

The main objective of the proposed scoping review is to identify the current best practices for treating the acute pain in individuals with opioid dependence or use disorder. It is anticipated that the results of the scoping review will inform healthcare providers of the best standard of acute pain management for this population and identify gaps for further research. The results will hopefully play a role in ensuring that opioid users receive the highest standard of care for acute pain.

A preliminary search of MEDLINE, Embase and scoping review protocol registries including the Open Science Framework was conducted. Only one previous review has looked at the management of acute pain in patients with opioid dependence.26 This 2020 review included patients taking medication for OUD, whereas this scoping review includes patients with opioid dependence regardless of treatment status. The previous study was also a rapid review which used a narrower search strategy, yielding less information sources. The search strategy for this scoping review is intentionally broader to try and capture all relevant literature on the treatment of acute pain in patients who are opioid dependent.