As the population ages the challenge of safe and appropriate pain management increases. Management challenges include age-related changes in physiology, increased risk of falls,224,225 pharmacodynamics and pharmacokinetics, higher prevalence of comorbidities and concurrent medications, altered responses to pain, and difficulties with assessment of pain severity and response to treatment, including problems related to cognitive impairment.
Consider the use of non-drug strategies such as movement, exercise, physiotherapy and psychological therapies as alternatives to, or in combination with, medication.226 Where opioids are used, consider risk assessment for falls and interventions to mitigate common risks of opioid therapy such as constipation. Also, monitor older patients for the presence of cognitive impairment.15,226
Despite the higher incidence of side effects with drug therapy in older people, analgesics may still be safely and effectively used if tailored for the individual patient and comorbidity and other medications are considered.226 However, analgesics should be:226
- initiated one at a time using a low dose
- monitored regularly and adjusted as needed to improve efficacy and limit adverse events • titrated slowly according to response
- used in combination where synergistic effects provide improved pain relief with fewer side effects than higher doses of a single drug.
When prescribing opioids to older adults, it is important to provide education about risky medication-related behaviours such as obtaining controlled medications from multiple prescribers and saving or stockpiling unused medications.15
Appropriate precautions must be taken when considering opioid therapy for older patients.227 These precautions include lower starting doses, slower titration, longer dosing intervals, more frequent monitoring and tapering of benzodiazepines.194,227 There is an increased risk of adverse effects including cognitive impairment, sedation, respiratory depression and falls.228,229 The risk of respiratory depression is minimised by monitoring the patient for sedation and reducing the dose of opioid if this occurs.228
While there are large individual differences, older patients are more sensitive to opioids and dose requirement decreases progressively with age, often reduced by 50% or more. There may be fewer pharmacokinetic differences between older and younger patients with fentanyl,81 morphine, oxycodone230 and buprenorphine.108 However, in the clinical setting, there is evidence of an age-related 2–4-fold decrease in morphine and fentanyl requirements.231,232 In patients older than 75 years, the elimination half-life of tramadol is slightly prolonged233 and lower daily doses have been suggested.234
Older patients require less opioid medication than younger patients to achieve the same degree of pain relief; harms can also occur at lower doses than they occur in younger patients.231,232,235 However, inter-patient variability exists in all age groups and doses must be titrated to effect in all patients.