Text adapted in 2023 from "Opioid Use and Opioid Use Disorders" in The Primary Care Addiction Toolkit. Revised version available online only.
Options for managing chronic non-cancer pain
Chronic non-cancer pain is any pain condition that lasts for at least three months that is not associated with malignant disease. It affects activities of daily living and reduces physical function and quality of life. Clinical guidelines recommend non-opioid pharmacotherapy and non-pharmacological therapy rather than a trial of opioids (Busse et al., 2017). Opioids as an add-on therapy have shown a modest improvement in pain (reduction of 1 or 2 points on an 11-point scale) and functioning (10 per cent improvement); however, they carry a risk of overdose, physical dependence and addiction.
There is moderate evidence for using exercise and physical therapy, psychological therapy and self-management programs to ease chronic non-cancer pain (Centre for Effective Practice, 2018a). First-line non-opioid pharmacotherapies may achieve a similar reduction in pain without the harms associated with opioids.
The McMaster National Pain Centre (Busse et al., 2017) makes the following recommendations for managing chronic non-cancer pain:
- Initiate treatment with a trial of non-opioid pharmacologic therapy rather than an opioid.
- Stabilize active psychiatric disorders such as anxiety and depression before beginning a trial of opioids because these mental health conditions are risk factors for adverse outcomes.
- Prescribe opioid therapy only if other treatment options have not been effective.
- Avoid opioids for managing chronic non-cancer pain in patients with an active substance use disorder because this comorbid condition is a well-documented risk factor for adverse outcomes. Continue non-opioid therapy rather than starting a trial of opioids.
Some patients at high risk of addiction (e.g., history of mental illness, current or past problematic substance use) may be eligible for a trial of opioids if they have a persistent, problematic and well-defined pain condition that has not responded to other treatment. For example, the Canadian Pain Society recommends controlled-release opioids as a second-line option to manage neuropathic pain (Moulin et al., 2014). If there is no improvement after three to six months, the prescriber should discontinue the opioid.
Choosing an opioid to manage pain
To manage chronic non-cancer pain, start with weaker opioids such as codeine or tramadol for mild to moderate pain, and morphine or hydromorphone for severe pain, unless otherwise appropriate (Centre for Effective Practice, 2018a). If a more potent opioid is required, choose one that:
- has not been problematic for the patient in the past
- is not commonly misused in your local community
- has a lower misuse liability.
Minimizing adverse outcomes of opioids to manage pain
- Before beginning a patient on opioids to manage pain, use the following strategies to minimize adverse outcomes of opioid use (Centre for Effective Practice, 2018a):
- Explain that this is a trial of opioids, not a commitment to long-term prescribing of opioids. A trial consists of opioid dose titration and assessment of response in terms of improved pain and functioning.
- Educate patients about common side effects such as nausea, constipation, drowsiness and dizziness. Also explain that long-term opioid use can lead to opioid-induced sleep disorders, increased pain sensitivity and hormonal effects (e.g., secondary hypogonadism).
- Educate patients about risks and safe use of opioids, specifically the risk of overdose and addiction with opioid treatment that lasts three months or more. The risk of unintentional non-fatal and fatal overdoses increases with doses higher than 50 mg morphine equivalents daily (MED).
- Establish realistic goals and expectations for opioid therapy to reduce, not eliminate, pain and to improve function.
- Obtain a baseline urine sample to establish risk. The frequency of urine drug testing to monitor adherence to prescribed opioids may be determined based on each patient’s risk factors. Understand the limitations of urine drug testing and know how to interpret results (Centre for Effective Practice, 2018b).
- Monitor patients frequently through clinical assessments, and order urine drug tests periodically, when appropriate.
- Dispense small amounts of opioids frequently (e.g. weekly) and aim for the lowest effective maintenance dose.
- Have an “exit strategy.” Discuss how opioids will be discontinued if the patient does not experience enough benefit to outweigh the risks. For example, consider discontinuing opioids if the patient experiences significant adverse effects or recurrent aberrant drug-related behaviours.
- Obtain informed consent and consider creating a treatment agreement to clarify expectations, treatment goals and strategies to try if the opioid trial is not effective.
- Avoid prescribing CNS depressant medications together with opioids, when possible. If the patient is already on prescribed sedative and hypnotic medication, consider tapering them with a goal of discontinuation. Also be aware of concurrent use of alcohol and over-the-counter medications, which may increase the risk of overdose during initiation and titration of opioids.
Key safety messages about opioids
Make sure that patients taking opioids to manage chronic non-cancer pain understand these safety messages (Centre for Effective Practice, 2018c):
- Naloxone kit: Obtain a naloxone kit from the pharmacy in case of accidental overdose, especially for opioid doses of 50 MME per day or more. Family members can also get training so they can recognize the signs of opioid toxicity and know how to administer naloxone.
- Safe storage: Keep the medication away from others, particularly adolescents or young adults living in the same household, and do not share it with others. A dose that may be safe for you could be dangerous or even fatal for a non-tolerant person.
- Accidental overdose: Do not mix opioids with alcohol or sedating medications such as benzodiazepines or dimenhydrinate (Gravol) due to risk of overdose. Signs of overdose include slurred speech, sedation and nodding off during conversations, poor balance and labile mood.
- Driving or operating machinery: After a dose increase, do not drive until you know how the dose change affects you.
Monitoring opioid therapy in pain patients
Assess patients for dose efficacy and tolerability every two to four weeks during initial titration (Centre for Effective Practice, 2018c). Patients at higher risk for sedation (e.g., elderly, on benzodiazepines, renal or hepatic impairment) may be assessed more frequently after initiation or when the opioid dose changes.
Ask about and observe the five A’s (Maumus et al., 2020):
- Analgesic effects: “How well does the medication relieve your pain?” An important difference for pain is a reduction of two points on an 11-point rating scale (Busse et al., 2017).
- Activity: “Are you more or less active since your last visit?” Functioning should get better with improved analgesia.
- Adverse effects: “Are you feeling more sleepy than usual?” “Are you having any trouble with constipation?”
- Affect: “How is your mood?” Affect should get better with improved analgesia.
- Aberrant behaviours: “Do you alter how you take the medication?” “Do you ever take more than is prescribed?”
Having patients set specific, measurable, attainable, relevant and timely (SMART) objectives at the beginning of treatment helps them plan the steps to meet their long-term goals. Reviewing SMART goals at each follow-up is a meaningful way to monitor progress, with a focus on functional improvement and realistic expectations for pain improvement.
A helpful tool for assessing chronic non-cancer pain and functioning is the Brief Pain Inventory (Tan et al., 2004). Patients use it to report the severity of their chronic non-cancer pain, their response to opioids and how opioids affect their mood, sleep and functioning.
