Principles of Patches
The most common analgesic drug used in transdermal patches is Fentanyl, but Buprenorphine can also be delivered transdermally. Patches provide background analgesia only, so short-acting analgesia should also be prescribed for breakthrough pain.
Always co-prescribe Naloxone (Opioid Toxicity)
Fentanyl patches have a limited place in pain management and their strength is often underestimated. Fentanyl Patches Fentanyl patches should only be initiated after specialist advice.
Buprenorphine patches must NOT be prescribed by anyone in the Trust. If a patient is admitted to the Trust already established on buprenorphine for analgesia this could be continued, or changed to a more familiar opioid whilst in hospital: Buprenorphine Patches
Patches must be placed on clean, dry, non-hairy intact skin. Once a patch is applied, transdermal analgesia takes up to 24 hours to reach steady plasma levels so other analgesia should be available in the meantime. Conversely, once the patch is removed, opioid plasma levels will take around 24 hours to reduce, so the patient should continue to be monitored for signs of opioid toxicity, particularly if other opioids have been prescribed.
Patches are not licensed for acute post-surgical pain due to variable absorption in the early post-operative period:
- hypovolaemia with peripheral vasoconstriction will reduce drug absorption through the patch;
- sweating will reduce adhesiveness so will reduce absorption;
- pyrexia due to patient factors such as sepsis, or external factors such as patient warming devices, will increase absorption.
If a patient has been established on a patch for long-term pain, and is due to undergo surgery which will result in unpredictable absorption, the patch should be removed and morphine started, based on the equivalence tables: Fentanyl Patches, Buprenorphine Patches