Approximately 50 per cent of those with chronic pain have musculoskeletal problems. The healthcare costs of managing pain are significant.
Initial treatment of acute pain is familiar to health professionals and patients, with usual approaches being appropriate use of rest, physical measures, simple analgesics and anti-inflammatory medications. The symptoms usually improve within a few days or weeks and they do not routinely require specialist pain management.
Those who develop persisting musculoskeletal pain may be referred to specialist services.
There are no commonly agreed recommendations for the management of most musculoskeletal pains, although there are guidelines for some.
Globally, back pain is another common disorder, affecting 10 per cent of the population and is one of the top 10 most expensive healthcare problems.
Inadequate information
There is a relative lack of knowledge about the pathophysiology of persistent musculoskeletal pain, a situation that may lead to patients lacking information about their condition and its management.
Management of musculoskeletal pain can be complex and no single approach will be adequate on its own.
While pharmacotherapy remains the mainstay of treatment for many patients, other approaches such as physiotherapy, injection treatments, acupuncture, TENS, psychological/cognitive-behavioural therapies and structured rehabilitation programmes all have a role as part of a multidisciplinary strategy. However, this review will focus on pharmacological management.
Prescribing options
The WHO analgesic ladder was developed for the management of pain associated with malignancy, but many of its general principles can be applied to musculoskeletal pain.
Most patients referred to specialist pain management services will already have been prescribed simple analgesia, such as regular paracetamol and/or NSAIDs.
Recent work suggested that any analgesic benefit of paracetamol and NSAID combination therapy is small compared with treatment using either class of drug alone. However, it is always useful to review patients' use of such medication, because many will not have taken the drugs regularly and appropriately.
The problem of gastric, renal and anti-platelet side-effects in those taking NSAIDs is well known. The adverse findings regarding cardiovascular safety in prolonged use with the selective COX-2 inhibitors has had a significant impact for pain management services and patients.
These issues have prompted a thorough review of NSAID use, and it would appear that there is some consensus that ‘traditional', non-selective NSAIDs are all equally effective.
There is a move away from long-term NSAIDs because of their toxicity, setting the scene for increasing use of opioids, which may be less organ toxic.
Physicians treating patients with chronic pain often debate the most appropriate patients and stage to use strong opioids in the treatment regimen.
Most health professionals have no problems with prescribing weak opioids, such as codeine and dihydrocodeine, and preparations such as tramadol. These are effective in managing moderate pain.
Tramadol has both opioid and non-opioid properties that interact synergistically. It can lead to gastrointestinal problems or sedation and, for this reason, the more recent lower dose preparation of tramadol combined with paracetamol may be more appropriate in some patients.
Strong opioids
The decision to prescribe strong opioids, such as morphine and its derivatives can be more troublesome for health professionals. Some physicians avoid prescribing strong opioids due to concerns about addiction and side-effects. However, it is important to prescribe according to the patient's needs to achieve the primary goal, to manage their pain effectively.
The physician should monitor the patient for the degree of pain relief, side-effects and improvement in function and quality of life.
The evidence for the use of strong opioids in treating musculoskeletal pain is both limited and conflicting.
However, while opioids should only be considered after the use of other established therapies, clinical experience has shown some benefit in their use for persisting musculoskeletal pain. They are effective both for nociceptive and neuropathic pain, and they also have anti-inflammatory properties.
Prolonged release preparations, such as morphine sulphate and oxycodone tablets, are preferable to short-acting drugs to achieve consistent analgesia.
Opioid switching - substituting one opioid preparation for another - can be useful because individuals differ in their response to different opioids. All strong opioids have the potential to cause gastrointestinal side-effects such as emesis and, more usually, constipation. Patients receiving strong opioids should usually also be prescribed a laxative.
Other delivery methods
Just as changing the type of opioid prescribed may be necessary in certain circumstances, so too may varying the method of delivery. Transdermal delivery (patch) systems are available for buprenorphine and fentanyl. Patch form Buprenorphine is available in the UK. The patch should be changed every three and seven days, respectively. Fentanyl has a range of high-dose patches, which should be changed every three days. A lower-dose 12µg/hour fentanyl patch is also available in the UK.
The starting dose for the high-dose patches can be too high for opioid-naïve patients.
The lower dose buprenorphine patch is available in three lower strengths and may be more suitable for patients who are sensitive to strong opioids. Transmucosal, oral and injectable opioids are rarely appropriate in this group of patients, as their use may lead to dose escalation and tolerance.
Adjunctive therapy use is less in musculoskeletal pain is less widespread. In some patients it may be appropriate to consider the use of such as anticonvulsants, antidepressants or muscle relaxants.
The benefits and burdens of efficacy and side-effects should be considered in each case.
- Dr Lawrie is a specialist registrar in palliative medicine and Dr Simpson is a consultant in pain management at the Pain Management Service, The Leeds Teaching Hospitals NHS Trust, Leeds, UK
- A version of this article was originally published in Pain Europe (2006;2:4 - 5). To receive regular copies or Pain Europe, email paineurope@subscriptions.co.uk or register online at www.paineurope.com
