The updated guidelines are available online and in the June print issue of MIMS. They can also be found in the new MIMS Cancer Clinic, an online resource centre that collates news and resources to support prescribing in cancer.
The summaries provide guidance on:
- Dose conversions between oral morphine and other opioid analgesics
- Initiating treatment with transdermal opioids
- WHO pain ladder for cancer pain relief in adults
- Co-analgesics for use in cancer pain
- Syringe driver drug compatibility
- NICE: recommendations on the prescribing of strong opioids for pain in palliative care of adults.
Initiating treatment with transdermal opioids
Most manufacturers of fentanyl patches now recommend two dosage conversions.
For patients who have been stabilised on a strong opioid over several weeks and who need opioid rotation, the recommended conversion ratio of oral morphine to transdermal fentanyl is 150:1.
For highly -opioid-tolerant patients on stable and well-tolerated opioid therapy for a long period, and who need opioid rotation, the conversion ratio of oral morphine to transdermal fentanyl is 100:1.
As conversion ratios are an approximate guide, careful monitoring during conversion is necessary to avoid both over- and underdosing.
Co-analgesics for use in cancer pain
The 5-step treatment pathway suggested by the Palliative Care Formulary for the use of adjuvant analgesics to treat neuropathic pain has been shortened to 4 steps:
- Step 1 - amitriptyline or gabapentin
- Step 2 - amitriptyline and gabapentin
- Step 3 - amitriptyline and an alternative anticonvulsant eg, valproate
- Step 4 - specialist measures eg, an NMDA antagonist and/or interventional anaesthesia.
Syringe driver drug compatibility
Advice on mixing two drugs in a syringe driver has been divided into combinations that are compatible, incompatible and those which require caution.
The compatibility advice applies to syringe drivers such as the McKinley T34 that deliver drugs by volume. Older devices (eg, Graseby syringe drivers) with delivery rates based on length rather than volume of liquid should no longer be used, following incidents of patient harm and death caused by incorrect rate settings.