Difficult painBMJ 2006; 332 doi: https://doi.org/10.1136/bmj.332.7549.1081 (Published 04 May 2006) Cite this as: BMJ 2006;332:1081
- Lesley Colvin, consultant anaesthetist,
- Karen Forbes, professorial teaching fellow in palliative medicine,
- Marie Fallon
- department of clinical neurosciences, Western General Hospital, Edinburgh
- Bristol Oncology Centre.
Pain occurs in up to 70% of patients with advanced cancer and in about 65% of patients dying from non-malignant disease. In about 10% of these patients the pain is difficult to control. Their pain often falls into one of three categories: it responds poorly to opioids, it is episodic and breaks through despite background opioid analgesia, or it is caused by non-physical factors such as psychosocial distress.
Pain that responds poorly to opioids
The European Association for Palliative Care guidelines on the use of morphine and alternative opioids in cancer pain confirm oral morphine as the opioid of choice for moderate to severe pain. If the pain is uncontrolled with a dose of morphine that gives the patient intolerable side effects, suggested measures include exploring psychosocial issues, managing the side effects, reducing the dose of opioid, switching to an alternative opioid, or changing the route of administration. The use of adjuvant drugs or co-analgesics may be appropriate. Many such patients will have neuropathic pain.
Nociceptive pain results from real or potential tissue damage. Neuropathic pain is caused by damage to the peripheral or central nervous system. Pain may be described as aching, burning, shooting, or stabbing and may be associated with abnormal sensation; normal touch is perceived as painful (allodynia). It may be caused not only by tumour invasion or compression but also by surgery, radiotherapy, and chemotherapy. If neuropathic pain does not respond to opioids, patients will require additional measures.
The early addition of adjuvant analgesics, such as a tricyclic antidepressant or an anticonvulsant, should be considered. The number needed to treat is 3 for both categories. There …