Opioids in chronic non-malignant pain

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Persistent pain is common, affecting around five million people in the UK. For many sufferers, pain can be frustrating and disabling, resulting in functional impairment - physically, emotionally and vocationally. Medications and other treatments that aim to reduce pain intensity play a role in the management of symptoms, but should be provided as part of a wider management plan focused on reducing disability and improving overall quality of life.

Opioids have been increasingly prescribed to treat chronic non-malignant pain. There is evidence from clinical trials that they can be effective, in the short and medium term, in providing symptomatic improvement in somatic, visceral and neuropathic pain. Complete relief of pain is rarely achieved. The goal should be to reduce pain sufficiently to facilitate engagement with rehabilitation and the restoration of useful function. The management of persistent pain focuses not only on reduction in pain intensity but also on improvement in sleep, mood, and physical, vocational, social and emotional wellbeing.

The safety and efficacy of opioids in the long term is uncertain, as is the propensity for these drugs to cause problems of tolerance, dependence and addiction. The benefits of opioid treatment for the patient must be balanced against burdens of long term use as therapy for persistent pain may need to be continued for months or years.

There is no good predictive factor of the analgesic effect of opioids in chronic non-malignant pain. If deemed appropriate, the individual should have a monitored opioid trial over a period of 6 weeks to determine the effectiveness of the treatment and the presence of side effects. If the clinical decision is made to continue the prescription of the opioid, there should be ongoing timely reassessment.

Recommendations are made on determining the suitability of an opioid trial, the choice of opioid, the conduct of an opioid trial and long term monitoring of the patient.  

The guidelines reviewed included the following: 

  • The British Pain Society (2010)
  • Sign 136 – Management of Chronic Pain (Dec 2013)
  • U.S. Department of Veterans Affairs/Department of Defence (2010)
  • The Canadian Guidance (2010)
  • Guidelines for South Australian GPs (2009)
  • American Pain Society-American Academy of Pain Medicine (APS-AAPM) Clinical Guidelines for the Use of Chronic Opioid Therapy in Chronic Noncancer Pain (2009)

 

Guidance for the Safe and Effective Prescribing of Opioids for the Management of Chronic Non-Malignant Pain: initiation, monitoring and tapering

This guideline is to aid primary care teams in managing patients, who have chronic pain, with opioids. This guidance should be used in conjunction with local and/or national guidance on the assessment of pain and with reference to British Pain Society Guidelines.

Key Points

  • The aim of using opioids in the short to medium term is to support the rehabilitation and restoration of physical and mental function of patients.
  • Clinical evidence has demonstrated that opioids can be useful in the management of chronic somatic, visceral and neuropathic pain.
  • Opioids can also have untoward effects in terms of tolerance, dependence and addiction.

Before initiating opioids consider the following:  

  • What is the cause (diagnosis) of persistent pain in your patient?
  • Has a biopsychosocial assessment been made?
  • Have other appropriate methods of pain management been tried? (e.g. other medications, graded exercises, pain management strategies, psychological methods)
  • Does your patient have neuropathic pain? (Refer to NHSH neuropathic pain guidelines)
  • Would a trial of opioids be suitable for this patient? (see below)
1. Contraindications

There are no chronic pain conditions in which opioids are completely contraindicated, however the boxes to the right are situations where they are not recommended or where closer monitoring would be required.

Consideration should be given to using the Opioid Risk Tool to assess for potential high risk/dependent patients. If patients are assessed as moderate to high risk closer monitoring will be required.

 

2. Initiation of Opioids

Prior to the commencement of opioid therapy, it is essential that appropriate informed consent is obtained from the patient and if necessary family/carers. The discussion should include;

  • A clear explanation of the advantages and disadvantages of opioid therapy, which should include short term and long term side effects, potential for tolerance and addiction, detrimental impact on quality of life and advice on driving and operating machinery as per the British Pain Society Information Leaflet. http://www.britishpainsociety.org/book_opioid_patient.pdf
  • Agreeing achievable patient specific goals. This may include an agreed expected reduction in pain score (30%), improvement in sleep pattern and functional ability. 
  • An explanation of the concept of an Opioid Trial and what circumstances would surround the discontinuation of opioid medication.

Completion of the 1st page of the ‘Progress Note’ Pain Assessment & Documentation Tool (PADT) to record baseline levels of the pain score and functional ability with help with assessment if treatment is been of benefit. http://www.healthinsight.org/Internal/assets/SMART/PADT.pdf.

3. Opioid Trial

Length of trial: Anticipated length of each opioid mediation trial would be 6 weeks.

Expectation: 30% improvement in pain and/or significant improvement in functional ability and sleep pattern.

 Stop all analgesia listed below but continue with paracetamol/NSAIDs and neuropathic agents 

 Single or combination opioid analgesics containing:

  • Co-codamol
  • Co-dydramol
  • Codeine
  • Dihydrocodeine

 

 Commence trial

 

 

Starting Dose

 

Titration

Maximum

Dose 

1st Line

Tramadol Capsules

(Modified release)

100mg (modified release)morning & night

Increase by tramadol 50mg (immediate release) every week

400mg in 24 hours.

Once effective or maximum dose has been achieved the total daily dose should be converted into Tramadol Capsules (modified release) morning and night.

 

2nd Line

Morphine Sulfate Modified Release

10mg (modified release) morning and night

Increase by 10mg (modified release) morning and night - every 2 weeks

60mg morning and night(120mg in 24 hours)

  • If no response with tramadol (after full titration) at 6 weeks stop and convert to morphine as described above.
  • If tramadol is not tolerated due to side-effects, try sustained release morphine as described above
  • Avoid using short acting opioid for breakthrough pain.
  • If no response to MST (after full titration) after 6 week trial de-escalate dose by 10mg every week till stopped. This trial indicates that the patient pain is unlikely to be opioid responsive and this should be explained to the patient.
  • Reassess the patient 1 to 2 weekly.
  • Ensure most cost effective brands are used as identified from the NHSH Formulary.

 

4. Regular Assessment

Use of PADT tool for ongoing assessment is recommended (http://www.healthinsight.org/Internal/assets/SMART/PADT.pdf)

Assessment should include:

  • Ongoing Efficacy – carry out recordings of pain score and functional assessment.
  • If the opioid trial is not successful, discontinue opioid by tapering dose, reducing by 10mg of morphine every week till stopped.
  • There are no high quality randomized controlled trials to suggest that one opioid is more effective than another. If there is NO clinical benefit with a full trial of one opioid, we would discourage further opioid trials in primary care – seek opinion of Chronic Pain Specialist. If opioid trial is successful, continue with monitoring of dose, pain score, function and side effects every 3 months initially until dose is stable, then every 6 months. Consider weaning opioids every 6 months to see if dose is still optimal.
  • Keep daily dose of long acting opioid as low as possible.
  • Measure sex hormones if patient reporting symptoms of hypogonadism and if abnormal seek advice from local endocrine clinic.
  • Observe for signs of drug abuse. Refer to the Opioid Risk Tool
5. Treatment of Side Effects - further information

Constipation

The majority of patients taking opioids for moderate to severe pain will develop opioid induced constipation; tolerance does not develop to this side effect.1 If increasing fluid and fibre intake is insufficient, guidelines suggest that the best prophylactic treatment for opioid induced constipation is a combination of a stimulant laxative and a stool softener.1 Refer to NHSH formulary.

Nausea/Vomiting

Nausea and vomiting are common when starting on opioids but generally tolerance develops after 5-10 days.1 It is recommended that patients commencing on an opioid for moderate to severe pain should have access to prophylactic antiemetics to be taken if required.1 Refer to local formularies for treatment of choice. 

Itch

Opioid induced itch occurs in around 1% of those who receive a systemic opioid.  It is thought to be caused by a central mechanism rather than by histamine release, therefore in some cases antihistamines are not effective.4 Emollients should be used liberally if the patient has dry skin. Trial of a sedating antihistamine such as chlorphenamine or hydroxyzine is suggested, if this is not effective after a few days it should be stopped.6 

6. Renal Impaired patients

For those patients with renal impairment, the likelihood of opioid toxicity with any opioid increases and the following guiding principles should be followed when prescribing opioids; 

  • Use the smallest effective dose/frequency.
  • Titrate carefully and monitor for adverse effects.
  • If there are clinical concerns consult local renal specialists.
  • If patient has significant renal impairment seek advice from Chronic Pain Service and or Renal Specialists.

Add link to pain management in renal impairment guidance here

7. Treatment of very frail or older people

For those patients with chronic non malignant pain you should be guided by individual circumstances and co-morbidities and need not follow guideline recommendations lower doses are likely to be used.

References
  1. http://www.britishpainsociety.org/book_drug_misuse_main.pdf
  2. http://www.britishpainsociety.org/book_opioid_patient.pdf
  3. http://www.healthinsight.org/Internal/assets/SMART/PADT.pdf
  4. Sign 136 – Management of Chronic Pain December 2013
  5. NHS Highland Formulary 2013 to 2015
  6. BNF 69 – March 2015 to September 2015
  7. Greater Glasgow Non Malignant Pain Opioid Prescribing Guideline - November 2014
  8. Webster LR, Webster R, Predicting aberrant behaviours in Opioid treated patients: preliminary validation of the Opioid Risk Tool. Pain Medicine. 2005; 6(6):432
Opioid Equivalent Doses - these doses are an approximate and should be used as a guide

This table is an example for Primary Care clinicians to assess the strength of oral morphine between other forms of opioid medications available. This may help prescribers explain to patients the strength of their medication as many patients do not realise they are taking strong opioid medication until it is explained in the same strength as oral morphine.

Opioid medication

Approximate equivalent oral morphine in 24 hours

Co-Codomal (30/500mg) - 2 tablets 4 times a day (oral)

Oral Morphine 24mg

(1mg oral morphine = 10mg of codeine)

Codeine 30mg – 2 tablets 4 times a day (oral)

Oral Morphine 24mg

(1mg oral morphine = 10mg of codeine)

Dihydrocodeine 30mg – 2 tablets 4 times a day (oral)

Oral Morphine 24mg

(1mg oral morphine = 10mg of dihydrocodeine)

Tramadol 400mg daily eg 2 x 50mg capsules 4 times daily or 200mg MR twice daily (oral)

Oral Morphine 40mg to 80mg

 

Oral Oxycodone 5mg

Oral Morphine 10mg

 

Buprenorphine patch 5 microgram/hour

Oral Morphine 10mg / 24 hours

 

Buprenorphine patches10 microgram/hour

Oral Morphine 20mg / 24 hours

 

Buprenorphine patch 20 microgram/hour

Oral Morphine 40mg to 45mg / 24 hours

 

Buprenorphine patch 35 microgram/hour

Oral Morphine 60mg to 80mg / 24 hours

 

Buprenorphine patch 52.5 micrograms/hour

Oral Morphine 90mg to 120mg / 24 hours

 

Buprenorphine patch 70 microgram/hour

Oral Morphine 120mg to 160mg / 24 hours

 

Fentanyl patch 12 microgram/hour

Oral Morphine 30mg / 24 hours

 

Fentanyl patch 25 microgram/hour

Oral Morphine 60mg / 24 hours

 

Fentanyl patch 50 microgram/hour

Oral Morphine 120mg / 24 hours

 

Fentanyl patch 75 microgram/hour

Oral Morphine 180mg / 24 hours

 

Fentanyl patch 100 microgram/hour

Oral Morphine 240mg / 24 hours