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Final version_Opioid supplement

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By Dr Rajiv Malhotra, Consultant Anaesthetist and Pain Specialist, Royal Liverpool and Broadgreen University Hospital NHS Trust

Current state of play

Chronic pain affects approximately 28 million adults in the UK, with this number likely increasing as the population ages.1 This places a significant demand on both primary and secondary care services.

The coronavirus pandemic has highlighted pressures and blockage points within the healthcare system in the UK and the impact of the pandemic is likely to be felt for some time to come. There were over 28 million fewer outpatient attendances between April 2020 and June 2021.2 In primary care, there were also 31 million fewer appointments booked between April 2020 and March 2021.3 This backlog is likely to be exacerbated further as the impact of long COVID becomes apparent.2

The delay in accessing specialist care will put further emphasis on the assessment and management of pain conditions in primary care. Therefore, a detailed understanding of the recommended management strategies for pain conditions is vital. Opioid prescribing can be part of the management plan, as long as the principles of safe opioid management are followed.

This article outlines the indications for opioid use, details of initiation and rotation, and implications of opioid prescribing for patients.

Definition of chronic pain

There are varying definitions of chronic pain but multiple surveys demonstrate the impact this condition has upon our patients and their quality of life. The International Classification of Diseases 11th Revision (ICD-11)4 states that chronic pain is ‘pain that persists past normal healing time and hence lacks the acute warning function of physiological nociception.’ Chronic pain is then divided into chronic primary and secondary pain. 

Chronic primary pain is defined as pain that persists for longer than three months and is associated with significant emotional distress or functional disability and that cannot be explained by another chronic condition.4 This new definition applies to chronic pain syndromes that are best conceived as health conditions in their own right. Examples of chronic primary pain conditions include fibromyalgia, complex regional pain syndrome, chronic migraine, irritable bowel syndrome, and non-specific low-back pain.

Chronic secondary pain syndromes are defined as pain that may initially be regarded as a symptom of other diseases having said disease being the underlying cause. However, a diagnosis of chronic secondary pain marks the stage when the chronic pain becomes a problem in its own right. In many cases, the chronic pain may continue beyond successful treatment of the initial cause; in such cases, the pain diagnosis will remain, even after the diagnosis of the underlying disease is no longer relevant. Examples of chronic secondary pain are chronic pain related to cancer, surgery, injury, internal disease, disease in the muscles, bones or joints, headaches, or nerve damage.

It is important to note that patients can have a mixed picture of both chronic primary and secondary pain; patients with an initial diagnosis of chronic primary pain may develop mixed or secondary pain, based upon new investigations or the progression of symptoms. NICE estimates that only 1–6% of the population may have chronic primary pain, with a background chronic pain prevalence of approximately 40%.5

Epidemiology of chronic pain

The varying definitions of chronic pain can hamper the understanding of the epidemiology of chronic pain. Public Health England included nearly 8000 adults and 2000 children in a health survey focusing on chronic pain.6 The prevalence of chronic pain ranged from 18% in 16–34 year olds to 53% in the over-75 age group. The incidence was higher in women, those in the Black ethnic group, and in people living in more deprived areas. 

The impact of chronic pain can be felt in multiple facets of a person’s life. It is associated with poor general health (physical, psychological, social)6 and an increased mortality.7

Challenges of chronic pain management

Patients with chronic pain can provide a challenge to all healthcare professionals, from primary to tertiary care services. The reasons are multitude but include: 

  1. Interplay between chronic pain and mental health
  2. Polypharmacy and drug interactions/side effects
  3. Impact on motivation for exercise
  4. Impact on family life and relationships
  5. Impact on employment and finances
  6. Impact on education
  7. Social isolation
  8. Limitations of diagnostic testing.

The complexity of chronic pain requires a multidisciplinary approach, and this should be embedded in primary care as well as the hospital setting. The role of the Primary Care Network is crucial in this regard, and as the prevalence of chronic pain increases, further funding of community pharmacy, physiotherapy, and psychology services may be required. 

National guidance for the management of chronic pain

There are several NICE guidelines that focus on the management of patients with chronic pain, with the most recent guidance addressing chronic primary pain management specifically.5 The definition of chronic primary pain adopted by NICE is pain that has ‘no clear underlying condition or the pain (or its impact) appears to be out of proportion to any observable injury or disease.’ 

The guidance promotes the use of exercise and psychology, as well as acupuncture. With regards to medication, the guidance recommends the off-label use of antidepressants but highlights multiple medications that are not recommended, from gabapentinoids to local anaesthetic injections. 

Opioids are not recommended by NICE for the management of chronic primary pain.5 However, NICE recommends shared decision making for patients with chronic primary pain who are already established on opioids. One should explain the lack of evidence and agree a shared plan to continue safely (if the benefits outweigh the risks) or to reduce the medication and eventually stop it. This is an important principle as patients may be concerned that this guideline will result in widespread cessation of opioids without appropriate consultation. Firstly, it is important to note that this guidance applies only to chronic primary pain and not chronic secondary pain or mixed pain conditions. Secondly, the guidance highlights that a discussion is needed between the patient and healthcare professional to decide on the risk/benefit profile of continuing and stopping opioid medication.

Initiating opioid medication

A number of steps are needed before a decision to commence opioid treatment in a patient with chronic pain can be made. A comprehensive history of the symptoms and their impact upon the patient is needed, along with the therapies already tried and their relative impacts. Whilst mental health disorders are not a contraindication to opioid prescribing, it is important to recognise they are a risk factor for opioid addiction. There are specific tools to screen for the potential risk of opioid misuse, such as the Opioid Risk Tool.8 Discussion with the patient’s mental health team may be useful. 

There is no optimum ‘time’ to start opioid therapies – they should not be the first step of a management plan – but equally delaying them may be denying patients a potentially useful medication. Input from a multidisciplinary team is likely to be beneficial, and will ensure that ‘non-opioid’ strategies are explored first, such as physiotherapy and psychology input. 

Shared decision making is key when initiating opioids,9 and patients need to understand the lack of evidence for long-term benefit in chronic pain; however it is accepted that some patients do benefit from opioids.9 The patient should be counselled that ‘curing’ chronic pain with medication is not the goal and is often unachievable, even with high doses; opioid medications are part of a wide management plan that focuses on improving quality of life within the context of pain. The discussion should also cover the potential for side effects (e.g. constipation, nausea, pruritus) and long-term complications, such as addiction. 

Opioid initiation should begin with an opioid trial, during which an opioid medication is started for a period of time (usually 2–4 weeks) followed by an assessment according to pre-agreed demonstrable objectives (e.g. 25% reduction in pain scores, ability to complete physiotherapy sessions, discontinuation of another medication). A patient diary can help inform the assessment. This approach further highlights the role that opioids can play in pain management and tries to focus on improved quality of life, rather than a focus purely on pain scores. If the opioid medication did not help the patient achieve the objectives or the side effects outweighed any benefits, then the patient may not benefit from opioids and alternative strategies should be explored. The choice of opioid for the trial is dependent upon the patient history and the characteristics of the pain; in most circumstances, a suitable choice would be oral morphine. 

If the patient benefitted from opioid therapy during the trial, a further discussion about long-term opioid use is needed. The discussion should focus on the evidence base for opioids, the problems with opioid use (including addiction) and the potential benefits, as informed by the opioid trial. It is important to identify functional outcomes that opioid therapy will assist with, as well as the potential for reduced pain scores. 

Once an opioid is started, the patient should be reviewed within 4 weeks to ensure appropriate use, identify side effects and assess the benefits of the drug. Once a stable regime is implemented, the patient should be reviewed every 6 months. Reviews should focus on the 6As:10 

  • analgesic efficacy 
  • adverse effects 
  • aberrant behaviours 
  • activities 
  • affect 
  • accurate records. 

A ceiling dose of total oral equivalent morphine should be agreed and documented in the clinic notes. The Faculty of Pain Medicine recommends a maximum of 120 mg of daily oral morphine.9  

Choice of opioid and starting dose 

There is no ‘first choice’ opioid for chronic pain use; each opioid has advantages and disadvantages and the choice is an interplay of patient factors, pain characteristics, and drug profiles. Often, oral morphine is chosen, as it is familiar and easily titrated. If a patient has constant pain during the day, slow release formulations are useful. If the pain is more episodic and short lived, immediate release oral morphine may be preferred. Patients with swallowing problems would benefit from transdermal patches. Injectable opioids, orally administered fentanyl, and pethidine are not recommended for chronic pain. 

The starting dose of opioid will vary dependent upon what medication the patient currently takes or has taken in the past. Generally, opioid medication should be started at a low dose and titrated upwards based upon efficacy and side effects. 

Stopping opioid medication 

If the opioid trial does not result in improvements in the outcomes identified, then reduction and cessation should occur. This is likely to be accepted by the patient if there was an agreement made at the beginning of the trial. 

Opioid reduction and cessation may be necessary in patients who have been established on opioids if there is no longer any benefit or if the side effects are unmanageable. It is important to discuss alternative management strategies with the patient to allay any fear. An assessment by the multidisciplinary team is useful to ensure that a comprehensive appraisal of potential strategies is made and discussed with the patient. 

Opioid reduction should be decided with the patient, backed up with an explanation of the rationale. The dose reduction should be gradual and complemented with regular reviews to assess for withdrawal symptoms. For very high opioid doses or complex opioid regimes, admission to an inpatient hospital bed for the weaning period may be needed. 

A 10% weekly or monthly reduction in opioid dose is usually appropriate. This will need to be reviewed regularly. Complete cessation of the opioid may not be feasible in the first instance, and may require several rounds of opioid reduction. Patients with mental health disorders may need more intensive support during the opioid reduction period. 

Opioid withdrawal 

Opioid withdrawal describes a cluster of symptoms and signs (e.g. sweating, shaking, diarrhoea, loss of appetite, tachycardia) associated with a reduction in opioid blood levels, sometimes seen with opioid reduction regimes. A 10% reduction in opioid does not usually cause withdrawal but is likely to be associated with anxiety, which can mimic withdrawal. The Clinical Opiate Withdrawal Scale is a useful tool to identify true opioid withdrawal.11 Regular assessments and support for the patient is needed. Occasionally, a slower reduction regime is needed. 

Addressing patient concerns about opioids 

Often patients will have concerns about starting morphine-type drugs and it is important to address them. This should form part of the shared decision making process, and patients should be reassured that the rate of addiction is likely to be low.8 There are no accurate prevalence figures for the prevalence of addiction amongst patients in the UK who are taking opioids for the management of chronic pain. We can identify patients at higher risk of developing addiction, using questionnaires such as the Opioid Risk Tool.8 Urine drug screening is rarely used within clinical practice in the UK for this cohort of patients. Opioids Aware is an online resource created by the Faculty of Pain Medicine, aimed at providing patient (and professional) information and this has a useful section on addiction.9  

Opioids and driving 

Patients who are started on opioid therapy need to be informed about the implications on driving. All opioid medications have the potential to impair driving and high doses are more likely to do so; if a patient is taking more than 220 mg of morphine a day, their driving may be impaired as much as someone who drives while above the legal alcohol limit.12 At such doses, the patient should be informed that they are unlikely to be fit to drive. If their driving is impaired as a result of taking opioids, it is illegal to drive. It is unsafe to drive in the first few days after starting or changing a dose of an opioid. Also, there is an interaction between alcohol and opioid medications that may result in unsafe driving at a lower opioid dose. 

Case study 1

Case study 2

Case study 3

When to refer patients who are on opioids to secondary care services 

  1. Above 120 mg of oral morphine (equivalent) per day9  
  2. Potential opioid misuse 
  3. Complex opioid prescribing – multiple opioids, organ failure 
  4. Complex psychological and mental health disorders. 


The burden and impact of chronic pain on the patient, their family and the health infrastructure cannot be underestimated. Opioid therapy remains an option for patients who suffer from chronic pain, but only as part of a holistic approach that includes non-pharmacological therapies such as physiotherapy and psychology. A full discussion with patients about the benefit and potential harm of opioid therapy are necessary, including a discussion about driving. 

Opioid choice and dose vary, but often morphine is considered an appropriate starting point. Close monitoring of opioid use if necessary using the 6As approach, with more than 120 mg daily morphine equivalent use prompting referral to secondary care.9 Opioid rotation often requires a 25–50% reduction in the equivalent dose to avoid opioid related side effects and complications.15 It is important to link opioid use to functional objectives, and not just a reduction in pain scores. Failure to achieve these agreed upon objectives should prompt consideration of opioid cessation. 

Key points

General considerations

References/suggested reading 

  1. Fayaz A, Croft P, Langford RM, et al. Prevalence of chronic pain in the UK: a systematic review and meta-analysis of population studies. BMJ Open 2016; 6: e010364. 
  2. BMA. Pressure points in the NHS. (accessed 14 September 2021) 
  3. Health Foundation. How has the COVID-19 pandemic impacted primary care? (accessed 14 September 2021) 
  4. Treede RD et al. A classification of chronic pain for ICD-11. Pain 2015; 156 (6): 1003–1007. 
  5. NICE. Chronic pain (primary and secondary) in over 16s: assessment of all chronic pain and management of chronic primary pain. Clinical Guideline 193. NICE, 2021. Available at:  
  6. Public Health England. Chronic pain in adults 2017. London: PHE, 2020. Available at: uploads/system/uploads/attachment_data/ file/940858/Chronic_Pain_Report.pdf  
  7. Da Silva J, Geenen R, Jacobs J. Chronic widespread pain and increased mortality: biopsychosocial interconnections. Annals of the Rheumatic Diseases 2018; 77: 790–792. 
  8. Webster LR, Webster R. Opioid Risk Tool. Pain Med. 2005; 6(6): 432. Available at:  
  9. Faculty of Pain Medicine. Opioids Aware. (accessed 15 September 2021) 
  10. Jovey R. Opioids, pain and addiction – practical strategies. British Journal of Pain. 2012; 6 (1): 36–42. 
  11. Wesson DR, Ling W. The Clinical Opiate Withdrawal Scale (COWS). J Psychoactive Drugs 2003; 35 (2): 253–9. Available at: default/files/ClinicalOpiateWithdrawalScale.pdf  
  12. Faculty of Pain Medicine. Taking opioids for pain. (accessed 15 September 2021) 
  13. Langford RM et al. Is tapentadol different from classical opioids? A review of the evidence. British Journal of Pain. 2016; 10 (4): 217–221. 
  14. Palexia SR prolonged release tablets SmPC. (accessed 27 September 2021) 
  15. Faculty of Pain Medicine. Opioids Aware—Dose equivalents and changing opioids. (accessed 6 October 2021) 

This promotional supplement has been commissioned and funded by Grünenthal and developed in partnership with Guidelines. Grünenthal suggested the topic and author, and carried out full medical approval on all materials to ensure compliance with regulations. The sponsorship fee included an honorarium for the author. The views and opinions of the author are not necessarily those of Guidelines, its publisher, advisers, or advertisers. No part of this publication may be reproduced in any form without the permission of the publisher. 



Date of preparation: October 2021