Introduction

Chronic pain is a common, complex and distressing problem, with wide‐ranging impacts on the individual, family, society and health service [1]. While chronic pain is often experienced as a sequela of injury or disease, it is not simply a symptom of other medical conditions but a distinct clinical entity, with its own medical definition and system of nomenclature [2–5].

Pain is a complex biopsychosocial phenomenon which presents as “An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage [6]. Chronic pain is pain that persists past the normal time in which healing would have been expected to occur; for most types of pain the transition from acute and chronic pain occurs after three months’ duration [2]. Unlike the management of acute pain, where the emphasis is on resolving the underlying cause, in chronic pain the emphasis is on managing the pain, addressing the effects of the pain and maximizing individual’s functional ability and quality of life [7].

Chronic pain has profound and diverse personal, social and psychological impacts, as well as economic consequences. The study ‘Pain in Europe’ found that the average duration for chronic pain was at least 7 years and that 1 in 6 people with chronic pain reported that their pain was sometimes so bad that they wanted to die [8]. The Global Burden of Disease (GBD) Study 2017 demonstrated that the high prominence of pain and pain‐related diseases are the leading causes of disability and disease burden in the world [9]. It is estimated that 40–60% of people living with chronic pain have inadequate pain management [10, 11].

Chronic pain affects one‐third to one‐half of the UK population [1]. Among people living with chronic pain, 10–14% have moderate to severe disabling chronic pain [1]. The majority of people with chronic pain contact their general (family) practitioner (GP)[12]; 10–15% of the population present to their GP due to chronic pain [13]. Patients with chronic pain are 1.5 times more likely to visit their primary care physician than those without chronic pain and 22% to 50% of GP consultations are related to pain [14]. Primary care delivers the overwhelming majority of pain‐related medical input; with only a small proportion, estimated at 0.3% to 2% of those with chronic pain, being seen each year in a pain clinic [14].

This chapter aims to address the management of chronic pain in primary care and takes as its starting point that all reasonable attempts to investigate and treat modifiable causes of pain have been made.

Management of Chronic Pain in Primary Care

The goal of treating chronic pain is to support the patient to live as well as possible, with the maximum quality of life, in spite of their chronic pain. This support can be considered in two primary categories: drug and non‐drug (including self‐management) interventions.

Chronic pain treatment must take into account an evaluation of the severity, impact and type of pain experienced [15]. Because of the complex biopsychosocial nature of chronic pain and the constrained time and resources available, the assessment and management of chronic pain in primary care can be challenging [16].

Initial assessment of people with chronic pain follows the standard consultation model of history taking and examination and should ideally include a history of the pain, functional assessment, behavioral health assessment, evaluation of other comorbidities, physical examination, imaging/diagnostic tests and other relevant tests [17]. Identifying and addressing the social challenges faced by patients with chronic pain, particularly with regards to the impact on relationships, employment and roles, is an important part of a holistic chronic pain assessment. Realistically, given the time constraints inherent to the primary care consultation, a full chronic pain assessment may well take place over a number of consultations. Pain severity can be evaluated in terms of pain intensity, pain‐related distress and functional impairment [18].

Agreeing Shared Treatment Goals

Evaluating patient‐reported outcomes is an important part of a comprehensive chronic pain assessment [19]. It can be beneficial for clinicians and patients to discuss and agree on treatment goals for chronic pain when reviewing or initiating treatment [17, 20]. Patients with chronic pain may be initially resistant to a shift in therapeutic goals from ‘pain elimination’ to ‘functional improvement’ however, it is vital to have such conversations during pain management in primary care, to ensure that the clinician and patient both have a common treatment goal [7]. Unrealistic treatment expectations can be a major barrier to achieving good management of chronic pain in primary care [20]. Achieving a reduction in pain intensity of 30–50% is generally considered to be a successful outcome [21], though success may also come from improving quality of life and function with minimal change in actual pain intensity. Evaluating treatments and interventions against this standard can help clinicians and patients to assess and contextualize their relative successes appropriately [7]. Clinicians should ensure that patients are aware from the outset that achieving complete freedom from pain is an unusual outcome [22].

Relevant Guidelines for Assessing and Managing Chronic Pain

Many guidelines for assessment and management of chronic pain are directly relevant to primary care. Key chronic pain guidelines exist in many countries, including Australia [23], Canada [8, 24, 25], Germany (26), the United Kingdom [15, 27, 28], the United States of America [8,29–31] and internationally [32–35]. The Scottish Intercollegiate Guideline Network (SIGN) Guideline, published in 2013 and updated in 2019, is a particularly appropriate tool for primary care physicians and makes a number of helpful recommendations for primary care physicians, a summary of which can be found in Table 13.1 [15]. This was the first, and remains the only, comprehensive evidence‐based guideline aimed at non‐specialists at managing chronic pain [15].

Drug Interventions

There is good evidence for the limited benefit of pharmaceutical interventions in many chronic pain conditions with 40–50% of patients obtaining some benefit. Detailed discussion of pharmacological management is beyond the scope of this chapter, but can be found in the cited guidelines above and elsewhere in this volume. While prescribing is one of the main responsibilities of any physician, it should not be the sole focus of a management plan. Furthermore, clinicians should engage patients in regular review of their prescribing to ensure that prescribed medications are optimized (effectiveness, adverse effects), rather than allowing prolonged issuing of repeat prescriptions without review.

It is important to assess and reassess chronic pain management and to ensure that each new treatment is given a long enough trial at a high enough dose (if tolerated) before moving on to other treatments. It is important to ensure that potentially effective treatments are not discarded because of an incomplete trial of treatment. Inappropriate timing or dose of drugs, poor medication compliance and unreasonable patient expectations for treatment can lead to the premature abandonment of potentially useful treatments.

The majority of people with chronic pain take analgesic medication. A large‐scale survey in Sweden found that almost half of all people with chronic pain were taking non‐prescription analgesics, including non‐steroidal anti‐inflammatory drugs (NSAIDs) (55%), paracetamol (acetaminophen) (43%) and weak opioids (13%). They found that two‐thirds of people with chronic pain were taking prescription analgesics, including NSAIDs (44%), weak opioids (23%), paracetamol (18%) and strong opioids (5%) [11].

With any type of chronic pain, paracetamol (acetaminophen) is generally the first drug of choice because of its good tolerability and efficacy [36, 37]. However, recent systematic reviews found that paracetamol was no more effective than placebo in chronic pain conditions [38, 39]. Any additional analgesic agents should be selected to target the type of pain, generally categorized into either ‘nociceptive’ or ‘neuropathic’. Nociceptive pain is traditionally associated with damage to tissues and is often due to historical trauma or injury, while neuropathic pain arises as a result of an injury (including disease or lesions) to the somatosensory system [40]. People with chronic pain may have mixed pain aetiology with both nociceptive and neuropathic elements and may therefore require a multimodal prescribing approach.

Neuropathic pain should be treated with appropriate neuromodulator analgesia, in a progression through tricyclic antidepressants, then gabapentin, then pregabalin [41]. In patients who have pain that is very localized, or where the use of neuromodulator analgesic is contraindicated or ineffective, consideration should be given to topical preparations, including lidocaine and capsaicin. When dealing with neuropathic pain opioids can sometimes be of benefit; however, while tramadol can be initiated in primary care, it is recommended that morphine only be initiated for neuropathic pain by secondary care physicians [41]. Any person who requires strong opioids for neuropathic pain should be considered for referral to secondary care pain management services.

If treatment of nociceptive pain is initiated with paracetamol, this could be augmented, as appropriate and providing there are no contra‐indications, with nonsteroidal anti‐inflammatory drugs (NSAIDs), such as ibuprofen and naproxen [37]. When considering using NSAIDs, clinicians must take into account patients’ age, comorbidities (including asthma, chronic kidney disease and risk of GI bleeding). Inappropriate NSAID prescribing for patients with chronic pain is common and poses an urgent patient safety risk [42]. Topical NSAIDs, such as ibuprofen gel, can be used effectively in many causes of chronic pain and have better safety than oral NSAIDs and comparable efficacy; however, they are not recommended for all types of pain [43]. Opioids have increasingly become a mainstay of the treatment for nociceptive pain; however, their risks of dependence, overdose, misuse, abuse, diversion, adverse events (e.g. falls) and death, when compared to other analgesics, mean they should be used with extreme caution [37, 44]. The SIGN guideline for chronic pain recommends that, “All patients receiving opioid doses of >50 mg/day morphine equivalent should be reviewed regularly (at least annually) to detect emerging harms and consider ongoing effectiveness. Pain specialist advice or review should be sought at doses >90 mg/day morphine equivalent” [15]. When reviewing patients’ use of opioids, clinicians should bear in mind that there is no evidence for their effectiveness in long‐term use, but that there is evidence for the above risks of potentially serious harms. The risk of clinical dependence and addiction means that once patients have been started on opioids it can be challenging to discontinue their use [29]. Patients on regular opioids should receive early reviews of any newly‐prescribed medication and a full medical review at least annually [15]

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