Management of chronic pain

Non-opioid drugs include paracetamol/acetaminophen and non-steroidal anti-inflammatory drugs (NSAIDs).^1,2 Paracetamol/acetaminophen is often preferred in the elderly although caution should be taken with regard to liver toxicity.¹ NSAIDs have lasting analgesic and anti-inflammatory effects across a range of chronic pain conditions.³ However, care should be taken with regard to the possibility of cardiovascular and gastrointestinal adverse events, and additional considerations should be taken in elderly populations and with concurrent alcohol consumption.^2-6

Other non-opioid drugs can be described as co-analgesic/adjuvant medications – therapeutics that were developed for an alternative purpose but have been found to provide analgesic properties.¹ The primary groups of co-analgesics are antidepressants and anticonvulsants.¹ While many antidepressants are effective in managing pain, they can be associated with a range of side effects, including weight gain, sexual dysfunction, cardiovascular effects, and lethality in overdose.² Similarly, anticonvulsants have been shown to improve quality of life and function in pain patients, but may lead to adverse events, particularly those associated with the central nervous system (e.g. dizziness, somnolence, gait or balance disturbance, and tremor).³

Topical analgesics can be applied directly to the skin at specific areas of pain.¹ The group of topical analgesics comprises very different mechanisms of action and can therefore not be described as one entity apart from the mode of application being topical. Topical non-steroidal anti-inflammatory drug (NSAID) analgesics inhibit cyclo-oxygenase enzymes, limiting the production of prostaglandins; for more information on NSAIDs, please see the non-opioid analgesics section.¹ Rubefacients cause irritation of the skin, which is believed to relieve musculoskeletal pain.¹ Other types of topical analgesics can bind to nociceptors in the skin and after repeated application, this can lead to ‘defunctionalisation’, which can reduce pain in the area.¹ Topical analgesics are less invasive than other treatments and their administration may limit systemic adverse events by minimising systemic concentrations of the drug.¹ However, local side effects including irritation, itching and rash may occur with topical analgesics.¹

Opioids can be divided into classical or atypical opioids.¹ Classical opioids exert their analgesic effect primarily through mu-opioid receptor agonism, whereas atypical opioids utilise multiple mechanisms of action, only partially relying on mu-receptor agonism.¹ Classical opioids and atypical opioids may be considered if pain remains poorly controlled following non-opioid approaches and if the benefit–risk ratio is favourable.^2,3 They should only be used in carefully selected patients, with risk factors for abuse and addiction reviewed prior to initiation.^3–5

When opioids are deemed necessary, they should be used at the lowest dose and for the shortest duration possible, with well-defined treatment goals and continuous evaluation.^2–5 Regular monitoring and follow-up should be implemented to ensure that opioids are used appropriately – and in alignment with realistic treatment goals for pain intensity and functionality, as agreed with the patient.^3,4,5 Dose adjustments may be made to find the right dose for each individual, and gradual down-titration should be considered and tailored to each patient.² Risk reduction, in terms of abuse, dependence and overdose, is key in cases where long-term opioid use is warranted.^2,3 For further information on the responsible use of opioids, click here.