Always take a brief history before prescribing analgesia to give the right type. Neuropathic pain, inflammatory pain and oncological pain all respond to different analgesia

Always consider whether the pain might be caused by a serious underlying problem. It is helpful to know the duration, onset & frequency of the pain. As well as any triggers or alleviating factors. This can guide whether further investigations or assessment is required. Additionally do not forget to review the observations.

Always check the renal function before prescribing & for any contraindications (allergy, peptic ulcer for NSAIDs etc.).

For patients under 50 kg or children, always check the BNF as lower doses are likely necessary to avoid overdose or toxicity

Use the WHO analgesic ladder when prescribing:

Step 1: Non-opioid ± adjuvants
  • Paracetamol 1 gram QDS: Those with low body weight (e.g. <50kg) or with risk factors for hepatotoxicity should receive 500mg QDS.
  • ± NSAIDs e.g. Ibuprofen 400mg TDS. Prescribe with PPI (lansoprazole 30mg OD) if long-term use. Avoid in the elderly, those with gastric ulcers, asthma or AKI/CKD. Be cautious in those with congestive cardiac failure.
  • Adjuvants can include anti-depressants, anti-epileptic medications, GTN spray, triptans for migraine, dexamethasone for malignancy, Buscopan for stomach cramps, benzodiazepines for muscle spasm etc.
Step 2: Weak opioid + non-opioid ± adjuvants
  • Codeine 30-60mg QDS. Often causes constipation so give with laxatives
  • Consider Tramadol 50-100 mg QDS. This is stronger than codeine and may have some neuropathic pain targets
  • Consider prescribing morphine sulphate oral solution (aka "oramorph") 2.5-5mg every 4 hours on the PRN section of the chart for breakthrough pain. It is good practice to prescribe this with anti-emetics, laxatives and naloxone (although nursing staff should always inform a doctor if they give naloxone)
Step 3: Strong opioid + non-opioid ± adjuvants
  • Calculate the 24h dose of morphine required from the use of oramorph on the PRN section, then prescribe this as regular modified-release preparations twice daily. Continue PRN oramorph at 1/6th of the daily dose of regular oramorph prescribed. 
    • For example, if 30 mg of oramorph is used, give Morphine Sulphate Sustained/Modified release 10-15 mg twice daily with one-sixth or 5 mg PRN immediate-release oral solution or "oramorph" for breakthrough pain
  • You will not be expected to start buprenorphine/fentanyl patches – the pain team will make this decision so contact them
  • You will also not be expected to start methadone prescriptions for opioid-dependent patients but you may be allowed to prescribe this for patients who take it in the community and have been admitted to hospital. Always double-check this dose with pharmacy!
  • Remember, opioids can cause nausea/vomiting, constipation and respiratory depression. It is good practice to prescribe them with regular laxatives, PRN anti-emetics and PRN naloxone.
  • If the patient has a poor renal function then consider oxycodone. This is twice as strong (i.e. 10 morphine = 5 mg oxycodone)
  • If giving subcut preparations, remember this is twice as strong as oral. So 10 mg oral morphine = 5 mg subcut morphine = 5 mg oral oxycodone = 2.5 mg subcut oxycodone
  • Pallcare.info offers a great tool for opiate conversion in palliative care patients
Before you move up the analgesic ladder, check the following:
  • If analgesia is prescribed regularly, is it at its maximum dose?
  • If analgesia is prescribed on the PRN side, has the patient used it at its maximum frequency?
  • Has analgesia been prescribed according to the pain ladder?
  • What type of pain is it and is the prescribed painkiller appropriate? E.g. neuropathic pain responds better to amitriptyline/duloxetine/pregabalin/gabapentin, trigeminal neuralgia responds better to carbamazepine
If the above is all correct and the patient is still in pain, then it’s time for…the local acute pain team!

Acute Pain Team
This service is often provided by specialist nurses (with support from usually a consultant anaesthetist) who advise on best pain management strategies. They are excellent at giving advice on appropriate agents, different types of pain, opioid conversions and advanced opiates such as patches or PCA. They are very helpful – but before contacting them, make sure that the WHO analgesic ladder is applied correctly or this will be their first advice.

Further tips:
  • For MSK conditions, paracetamol and NSAIDs are best. NSAIDs are highly effective for inflammatory pain e.g. gout, dysmenorrhoea
  • Be wary of paracetamol. It is easy to prescribe paracetamol with another paracetamol containing product e.g. co-codamol which can result in overdose
  • Avoid combing weak opioids e.g. dihydrocodeine/codeine with tramadol. They can cause confusion and drug errors
  • Some patients do not respond to codeine and so a low dose of a strong opioid may be appropriate to start
  • Always prescribe opioids with naloxone on the PRN side of the drug chart and document that nurses should contact you if they use it. Naloxone has a shorter half-life than most opiates and therefore multiple doses may be required
  • Do not prescribe laxatives with opioids if a patient has had bowel surgery with an anastomosis – this increases the risk of anastomotic leaks
  • Do not newly start patches for acute pain without expert guidance
Further reading:
Opioid dose conversion calculator: https://book.pallcare.info/index.php?op=plugin&src=opiconv

Nice guidance CG173: Neuropathic pain in adults: pharmacological management in non-specialist settings, published November 2013, Available at: https://www.nice.org.uk/guidance/cg173/chapter/1-Recommendations [last accessed 01/08/19]

World Health Organization, WHO’s cancer pain ladder for adults, Available at: https://www.who.int/cancer/palliative/painladder/en/ [last accessed 01/08/19]

Best Practice Advocacy Centre New Zealand, Best Practice Journal, 18 December 2008, Issue 18, pages 20-23, WHO Analgesic Ladder: which weak opioid to use at step two? Available at: https://bpac.org.nz/BPJ/2008/December/docs/bpj18_who_ladder_pages_20-23.pdf [last accessed 01/08/19]

Written By Dr Saman Jalilzadeh Afshari (FY2)
Edited by Dr Akash Doshi (CT1)