If opioids are no longer working
Cancer progressionThe most common reason for opioids to seemingly lose their effectiveness is the progression of the underlying cancer. This can result in new nociceptive (tissue damage) pain, which may respond to an increase in the opioid dose. If this dose increase is ineffective, this may be neuropathic pain.Neuropathic (nerve) pain can occur if the tumour is compressing or invading neural tissue. This type of pain typically responds poorly to opioids and any benefits may be outweighed by side effects. Tramadol and tapentadol are opioids which inhibit norepinephrine/ serotonin reuptake and noradrenaline reuptake respectively. Theoretically these actions mean they could be of benefit in neuropathic pain but the evidence to support this is currently weak. In the UK neither of these drugs are recommended for the treatment of neuropathic pain in the non-specialist setting, although tramadol may be used for acute, rescue analgesia (NICE, 2018).
Opioid induced hyperalgesiaThis should be suspected if the analgesic effect of an opioid is diminishing in the absence of disease progression. It is a paradoxical state of heightened sensitivity to pain due to long term exposure to opioids, the very treatment prescribed to alleviate it.Our understanding of opioid induced hyperalgesia (OIH) is emerging. Its incidence and precise etiology is unknown, although several theories have been proposed. Another feature that suggests OIH is diffuse allodynia -that is, a painful sensation in response to non-painful stimuli such as light touch.The mainstay of treatment for OIH is to reduce the opioid by gradually tapering the dose down. This may be difficult for patients to accept, particularly if their pain is, or has been, distressing. Specialist support is recommended.
Opioid analgesics: Treating Pain in People with Cancer
Our purpose is to transform access to education.
We offer a diverse selection of courses from leading universities and cultural institutions from around the world. These are delivered one step at a time, and are accessible on mobile, tablet and desktop, so you can fit learning around your life.
We believe learning should be an enjoyable, social experience, so our courses offer the opportunity to discuss what you’re learning with others as you go, helping you make fresh discoveries and form new ideas.
You can unlock new opportunities with unlimited access to hundreds of online short courses for a year by subscribing to our Unlimited package. Build your knowledge with top universities and organisations.