Many people with palliative care needs experience unacceptably high levels of pain. There is evidence to suggest that pain in palliative care could be better treated with existing approaches but barriers exist in the provision of optimal pain management in palliative care.  Barriers to patients receiving effective pain management can generally be grouped into three categories – those stemming from health care professional’s attitudes and knowledge, those stemming from patients beliefs and knowledge and those stemming from the health care system. In the non-palliative general population barriers to optimal pain management have been well researched and there is a tendency for providers to under assess pain and under treat pain in certain groups, like older people or children. [2,3] These suboptimal practices occur across a variety of clinical settings, from community care to emergency departments to acute hospitals and in palliative care. [1,4] In palliative care a number of groups have been specifically identified as being at risk of under assessment and under treatment of pain. These include people living in residential care and patients with cognitive impairment, [5,6] patients in neonatal, paediatric and adult intensive care units, [7-9] and members of minority ethnic communities. [4,10,11]
Barriers for health care professionals in optimising pain management in palliative care include failing to undertake adequate pain assessment by either failing to recognise the presence of pain, [8,9,12] or by failing to use validated assessment tools for specific patient groups. [1,13] One systematic review found that when health care professionals had less experience their accuracy when using pain assessment tools was low.  Another factor in suboptimal pain management is health care provider bias, which may manifest as prejudice against a particular group or the use of stereotypes to categorise a particular patient, or particular illness as not having pain. [9,13,14] Certainly the most vulnerable groups, the very young and the very old, are at greater risk for under assessment due to the misplaced belief that these age groups do not experience pain.  A systematic review which studied a range of interventions to address these problems did not show consistent improvement in patients’ pain severity, although patient satisfaction increased.  Several studies suggest that education of professionals in the post-graduate setting has the potential to improve outcomes for patients. [17,18] Noted in a recent systematic review the implementation of pocket cards, with information about symptom management in palliative care, were effective in improving pain management approaches for both adult and paediatric generalists with no experience in palliative care.  While internet-based training has been found to be efficient, neither it nor simulation based training has evidence for producing change in health care professional behaviour, although this area shows promise.  Previous exposure to palliative care training did show some benefit as did post-graduate rotations in palliative care services. Use of a pain algorithm by health care professionals has been shown to improve pain outcomes.  Nurse-led interventions including pain assessment, interdisciplinary collaboration, and medicines management, as well as educational interventions including the use of protocols, can improve patients’ understanding of their condition and their pain control. [1,14,20,21]
Patient and family/carer related barriers to pain management are also important. [15,22-24] The biopsychosocial nature of pain means that an individual’s knowledge and personal beliefs of pain and its treatment may greatly influence how well their pain can be managed.  In the palliative care setting patient related issues which may interfere with optimal pain management could include difficulty in accepting their prognosis, [9,14] a lack of knowledge regarding the various treatments for pain  and a fear of those treatments and their adverse effects. [11,26,27] As palliative care is increasingly provided in the community, family caregivers also play an important part in pain assessment and pain management. Gaps in caregivers’ knowledge and education have been identified. [28,29] Common issues with family and caregivers are a lack of understanding about analgesics and poor communication with palliative care providers.  Interventions targeting patients and their family/carers have been reviewed and have mixed results. Two reviews noted that interventions improved knowledge but did not result in improvement to pain scores or quality of life. [21,30] Another study demonstrated improved knowledge around pain management and improved patient satisfaction. 
Health system barriers to optimal pain management in palliative care include a lack of referral pathways and a lack of specialist services to refer to.  There are mixed results from the literature regarding the benefits of palliative care services on pain management. There was a strong correlation between positive pain management outcomes and referral to palliative care in HIV patients,  while there was limited correlation between the two in surgical patients.  A meta-analysis of 19 studies suggested that palliative care teams have a small but significant positive impact on patients’ pain, although the quality of the studies included was variable.  Improving referral pathways and referral triggers has proven to be beneficial in integrating palliative care services in intensive care units.  A systematic review of models of service delivery for cancer pain supports multidisciplinary pain consultation services, with referral via a clinical pathway.  The prevalence of uncontrolled pain is an important quality indicator for health services, and validated quality indicators are available. [35-39] The use of pain as a quality indicator is complex as multiple assessment tools are used within individual patient and disease groups and some patient cohorts are underrepresented. 
- Pain in palliative care patients should be actively identified, carefully assessed, and treated promptly. [1,41]
- Health care professionals should receive training in pain management for the palliative care setting and this training may be best repeated in both undergraduate and post graduate training programs. 
- Exposure to palliative care services through rotations are useful at improving generalists' knowledge and symptom management of patients. 
- Pocket cards and algorithms may also be useful to train staff who do not usually work in palliative care. Evidence-based protocols and educational processes within institutions should be developed to improve the quality of care. [18,19]
- A number of organisations have developed mobile apps to facilitate point of care decision making, such as palliAGED and palliMEDS.
- Discussing the pain management plan with patients and their families/caregivers is an important process which can improve overall symptom management and quality of life.  Checking patients and family/caregiver understanding of analgesics and ensuring open communication between them and the palliative care team could also greatly improve outcomes. 
- The best practice approach to pain management is proactive and multidisciplinary. Referral to a palliative care service may be beneficial to the patient and the family and may improve pain management outcomes.