Cautions

• If the patient has not had strong opioids previously
• With poor adherence of patches, e.g. patient with sweats or when applied to the chest wall of patients who are cachectic
• Rate of absorption is affected by changes in both ambient and skin temperatures making doses unpredictable, for example;
  • • Febrile patients, or patients with night sweats, should be monitored carefully for signs of opiate overdose
    • Patients should avoid saunas and sunbathing/tanning beds
    • Heat packs/hot water bottles should never be applied over the patch site
    • Heatwaves/holidays in hot climates can affect the patch. Counsel the patient to ensure the patch is not exposed to direct sunlight and they are aware of the signs and symptoms of opioid toxicity
• For MRI scans;
  • • Patches may contain metal, and/or be affected by heat generated during MRI scans. As MRI scan can increase body temperature due to changing magnetic fields during scanning and potentially alter drug release and/or absorption
    • Patches should be removed immediately before scans, and a new patch should be applied after the scan
• During the dying phase – seek specialist palliative care advice

General notes

• Patches come in two different formulations, reservoir and matrix
• Prescribe transdermal opioid patches by their brand names.
  Different brands have different formulations.  Where possible,
  patients should continue the same preparation type and brand to
  maintain analgesic effect;
  • • Matrix formulations contain the drug evenly distributed throughout the matrix; release of the drug from the matrix is controlled by the property of the matrix
    • Reservoir formulations contain the drug within a reservoir, and the rate of release of drug is controlled by a rate limiting membrane. Prescribing patches by brand name or specifying ‘matrix’ or ‘reservoir’ avoids confusion
• The rate of absorption is affected by increases in ambient temperature and skin temperature; changes in either of these can result in altered drug release and/or absorption, and increase the risk of respiratory depression and even fatal overdose
• Laxatives may require titration, as both buprenorphine and fentanyl
  are less constipating than oral opioids

Application

• Patches (particularly reservoir patches) should not be cut
• Where possible, patches should be replaced at the same time of day
• Patches should be applied to clean, dry, non-irritated and non-irradiated skin on the arms or trunk (note that patches may not adhere well to the chest wall of cachectic patients)
• When applying a patch, the date and time of administration should be written on the patch; this is particularly helpful when patients are moving between care settings, or there are multiple people caring for a given patient
• The patch site should be varied at each patch change to minimise the risk of skin irritation
• In confused patients, application to the upper back reduces the risk of unintended removal of the patch
• The patch should be checked at least once daily to ensure it is adherent to the skin. Creases or lifting at the edges will reduce absorption and may lead to suboptimal analgesia
• Dispose of patches by folding in half, sticky side together, and putting in safe disposal unit e.g. sealed bin, sharps box
• Patients can shower or swim, but often a vapour-permeable film dressing needs to be placed over the patch to aid adhesion