Chronic non-malignant pain affects approximately four million people in the United Kingdom (The Pain Society et. al. 2004). Many of these patients receive opioid therapy in a bid to reduce this pain, but for some people, a tolerance effect to their opioid drugs will occur [see 'Causes of Tolerance? below].
The pain society suggests that where tolerance is identified, prompt referral to a specialist multidisciplinary pain management service is required. The North Gwent Pain Team have responded to this by developing a nurse-led clinic utilising supplementary prescribing to provide a seamless service for patients. This service uses a five stage model based on behavioural change work undertaken by Miller and Rollnick (1991).
- Contemplation - the first stage of change, the patient considers his / her use of drugs and wants to change. The clinician?s role is to motivate the patient in their decision.
- Determination - this occurs when the patient has expressed a commitment to take action and decides to take steps to reduce the drug. The clinician?s role here is to help the patient find the most appropriate and effective strategies to achieve change including developing a realistic tapering schedule.
- Action - the action is agreed upon and the strategy for change is implemented. The clinician?s role is to enhance or maintain the patient?s role of self-efficacy. The clinician must also remain alert to the need to modify the action plan as needed.
- Maintenance - this stage will last a period of months, while the strategy to reduce the drugs is in progress. The clinician at this point must encourage and support.
- Relapse - if a relapse occurs, it is the responsibility of the clinician to help the patient get back on track. The action plan may need to be refined.
The initial consultation is face-to-face in clinic but much of the follow-up work is conducted over the telephone. Initially appointments are weekly, then fortnightly and eventually monthly as required. Alongside the reduction programme a multi-disciplinary approach to non-opioid treatment strategies are used. These may include exercise, relaxation, goal setting, pacing, non-opioid analgesia, TENS and acupuncture. It is also important to remember that:
- Excellent liaison with primary care throughout the process is essential.
- A review of all analgesia is required to ensure correct drugs are taken in correct dosages in an appropriate manner.
- Where there is more than one drug to reduce, it is necessary to decide which to reduce first (only work with one drug at a time).
- Any long acting preparations should be changed to standard release (with the exception of night-time dosages).
- One dose at a time should be reduced starting with midday and tea-time doses first, then working onto morning doses and last of all reduce night time doses.
- Very small reductions in dose should be made followed by a period of at least two weeks to stabilise on the new dose before a further decrease is recommended.
- If the change is not sustained, the patient should go back one step; the next step should be delayed until the patient is stable, then the gradual reduction should be continued.
- Reduce until the goal is achieved.
Causes of tolerance
Tolerance is caused by multiple distinct opioid receptor cellular adaptations and has been described as 'A state of reduced responsiveness to the effects of a drug caused by its previous administration. Increased doses are required to produce the same magnitude of effect previously produced by a smaller dose.? (The Pain Society et. al. 2004).
As drug side-effects are generally dose related, increased dosing leads to increased side effects occurring. These side-effects include: Respiratory depression, drowsiness, dry mouth, sweating, nausea and vomiting, slurred speech, hallucination, depression, headache, muscle rigidity, mood changes and decreased libido.
Miller. W., Rollnick. S. (1991) Motivational interviewing: preparing people to change addictive behaviour. New York: Gilford Press.
Pain Society., Royal College of Anaesthetists., Royal College of General Practitioners., Royal College of Psychiatrists. (2004) Recommendations for the appropriate use of opioids for persistent non-cancer pain. London: The Pain Society.