Improving access to effective chronic pain treatment

There is an increasing focus on rationalising pharmacological treatment of chronic non-malignant pain (CNMP) in order improve patient treatment and appropriately utilise healthcare resources. The prevalence of CNMP places a large burden on society and recent studies in Europe highlight national and socioeconomic costs attributed to chronic pain represent 3–10% of gross domestic product.¹ In the US, the burden of chronic pain is greater than that of heart disease and diabetes.² Due to the multitude of different therapeutic options and resources they demand, there are many barriers to provision of effective chronic pain treatment that have been well documented by the World Health Organization (WHO).³ While many are beyond the scope of the pharmacy profession, pharmacists can have an active role in improving knowledge and skills in the prescribing of chronic pain medications.

Increasingly in the management of chronic conditions, the use of treatment pathways to standardise and guide practice is providing a consistent evidence-based approach. The management of chronic pain is one such area where the use of treatment pathways, in conjunction with appropriate assessment tools, can provide non-specialist clinicians with the necessary information to treat patients effectively. Treatment of chronic pain remains difficult to treat pharmacologically, and there is no single analgesia that works for all conditions and underlying mechanisms. As such, the clinician must choose from a variety of drugs, all having different properties. The aims of any CNMP treatment pathway should be to provide a step-wise evidence-based approach to therapy.

The aim of any treatment guideline should be to provide evidence-based treatment options for clinicians to work through while empowering them to manage therapeutic issues such as treatment initiation, disease monitoring and adherence. This provides a consistent framework for symptom management. A successful therapeutic guideline for CNMP should:

Many non-specialist pain clinicians have neither the skills nor the time to provide appropriate musculoskeletal and neurological examinations when presented with CNMP. Improving the ability of non-specialist clinicians to differentiate between nociceptive and neuropathic pain will allow appropriate selection of pharmacological agents for treatment.

In the absence of consensus agreement regarding diagnostic approaches to chronic pain, the most effective method of chronic pain assessment is via screening tools.⁴ One such tool currently favoured by clinicians is the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) (Figure 1).⁵

Nociceptive CNMP originates from continuous innervation of pain receptors by noxious stimuli. As such, pharmacological therapy should target the pathways that result in production of pain and inflammation. An appropriate treatment pathway should mirror the WHO pain ladder.⁶ The evidence of benefit for these drugs lie in the area of acute pain management; however, the effectiveness of these agents can be assumed to transcend the acute/chronic pain classification, and so may provide effective analgesia.

Where the WHO pain ladder is followed, many patients require analgesia beyond that provided by regular codeine. Escalation of codeine to its maximum dose in appropriate patients (240mg/day) provides a level of analgesia equivalent to that of approximately 24mg oral morphine. Where regular maximum dose codeine is ineffective, and effectiveness should always be reviewed upon dosage increase, then clinicians should consider switching to modified-release opioid preparations. The documented number needed to treat (NNT) for opioids in chronic pain is around 2–4, making them effective tools for CNMP management.

The concern for many clinicians is the long-term use of opioids in a population where many patients can develop dependence, and side effects associated with long-term use. Good practice should recommend them as a third-line option in management of CNMP irrespective of nociceptive/neuropathic origin.⁷ To avoid dependence-related issues, and ensure patients receive appropriate care, non-specialists should be advised on a maximum dose of opioids up to which they should prescribe. Where patients require further dose increases, referral into specialist services should be advocated.

Clinicians should also be encouraged to utilise appropriate routes of administration where patients can take oral medications, because use of transdermal opioids comes at a much greater cost without much added benefit. As with weak opioids, where use is regular, co-prescribing of laxatives is advocated to minimise opioid-induced constipation.⁸

Development of a neuropathic treatment pathway, as with nociceptive pain, should focus on using evidence-based medicines while empowering non-specialist clinicians with information regarding treatment initiation and management. Unfortunately, because there are few direct comparisons between neuropathic agents, use of NNT and number needed to harm (NNH) allow a step-wise approach to neuropathic pain management.⁹ These treatment options provide effective therapy for a wide-ranging source of neuropathic pain disorders (generalised neuropathies). However where these treatment options become exhausted, either by treatment failure or tolerability, then referral to specialist services should be encouraged. Figure 2 highlights how an evidence-based, cost-effective treatment pathway for non-specialist pain clinicians would appear.

Tricyclic antidepressants (TCAs) have been shown to be effective at treating a multitude of neuropathic pain conditions and, as such, should be considered first-line therapies (NNT 2.5). Clinicians should be aware of the incidence of anti-muscarinic side effects, particularly in the elderly (NNH 14.7) and low dose initiation and slow dose increases are advocated. Where sedation is a concern, use of secondary amine TCAs, such as nortriptyline, are recommended over tertiary amines, such as amitriptyline.

Gabapentin has been studied in a variety of neuropathic pain conditions, and has been shown to be effective with a NNT of 5.4. The Scottish Intercollegiate Guideline Network (SIGN) guidelines for chronic pain suggest a high rate of adverse effects resulting in treatment withdrawal; however, this may be due to the rapid titration recommended over the first three days of therapy.¹⁰ Anecdotal evidence suggests that initial doses of 100–300mg daily titrated upwards in weekly intervals may improve patient tolerance.

Pregabalin is another gabapentinoid used frequently for management of CNMP. While the NNT is comparable to that of gabapentin, there are issues around tolerability in 18–28% of patients. Most common side effects are somnolence and dizziness. This is currently recommended for use after gabapentin therapy has failed due to cost–benefit comparison.

Duloxetine has a favourable NNT of 6, making it effective for use in diabetic neuropathy. Advantages for its use are derived from the dual action as both a neuropathic analgesic and antidepressant. As the incidence of CNMP has a deleterious impact on patient quality of life, this is an added benefit in those suffering depression secondary to CNMP.

Benefits of topical therapy for neuropathic pain are limited to localised neuropathies where oral medications have failed. Lidocaine 5% plasters are licensed in post-herpetic neuralgia; however, due to a questionable cost-benefit when compared with other medications, they are recommended only after more effective oral therapies have been used.

Improvements in access to treatment services should focus primarily on ensuring that patients are directed to appropriate resources at the earliest opportunity. This allows access to treatment suitable with the stage of care patients are in, and allows consistency in management. Of importance is that the implementation of any guidelines be undertaken using an active approach such as educational presentations and feedback sessions, rather than simple dissemination of the guideline. This ensures that clinicians are engaged in the process, and are aware of the appropriate use of referral pathways, which, in themselves, may avoid future referrals and so improve use of resources.

Several areas that may improve patient access are detailed below.

Early in a diagnosis of CNMP non-specialist pain clinicians are commonly charged with managing the patients. There is a well documented lack of confidence in managing chronic pain conditions, and this can lead to referral to specialist services unnecessarily.11 The focus should be to empower non-specialist clinicians to manage these patients with evidence-based medicines as part of an overarching treatment plan. Guidelines, such as the one mentioned in this article, can serve to direct pharmacological treatment, advise on monitoring and review of medicines. Utilisation of such a guideline can ensure that the inexperienced clinician avoids specialist advice unless necessary.

Use of visual diagnostic and treatment aids such as those displayed in Figures 1 and 2, allow the patient to understand their diagnosis and visualise the therapeutic path they are on. By sharing and discussing this step-wise approach, clinicians can provide patients with confidence in their treatment, vital in a condition that is difficult to treat. This can aid with patient adherence and, ultimately, treatment success.

Any guideline for CNMP management should ensure that where the treatment options within the recommended pathways are exhausted, there are clear points for specialist referral. This ensures only treatment-resistant patients, appropriate for specialist inputs are advanced towards such care, utilising resources effectively. This also allows direction in prescribing, promotes consistency in approach and when policed, reinforces the required patient progression to specialist services.

Once specialist input into care commences, it is essential that clear and detailed information regarding changes to therapy are transferred efficiently. This will allow seamless changes to patient therapy to occur and avoid continuing treatment with ineffective/unsuitable medicines to ensure new therapy is started in a timely manner.

CNMP continues to remain a challenging condition to manage for patients and clinicians, and inconsistencies in practise result in inappropriate use of healthcare resources. Appropriate assessment of CNMP, and initiation of pharmacological therapies selected from evidence-based treatment guidelines remain the most effective way to ensure patient receive successful therapy. Coupled with clear and regulated referral pathways to pain specialists, this approach can help to ensure pharmacological management of CNMP provides patients with safe and effective treatment while promoting responsible use of healthcare resources.

• Improving education and assessment skills during the patient consultation can direct prescribers to the most effective therapies.
• Identification of nociceptive or neuropathic pain types is essential.
• Opioids have a role in the management of chronic non-malignant pain; however, referral to specialist services should occur before patients escalated to large doses to ensure appropriate management of potential opioid dependence.
• Locally developed treatment pathways promoting cost-effective evidence-based practice will ensure that patients receive the most effective therapies earlier in their care and ensure consistency in non-specialist clinician approach.
• Specified points for referral during the treatment pathway allow clinicians to utilise specialist services at appropriate stages in patient care.