Fentanyl Transdermal Patch (Elderly Chronic Pain)

EQUIANALGESIC CONVERSION (opioid-tolerant patients): (1) calculate the 24-hour dose in mg/day of the current opioid; (2) convert to the equianalgesic 24-hour ORAL MORPHINE dose using the SPC multiplication factors — morphine oral 1, morphine parenteral 3, buprenorphine sublingual 75, buprenorphine parenteral 100, codeine oral 0.15, codeine parenteral 0.23, diamorphine oral 0.5, diamorphine parenteral 6, fentanyl parenteral 300, hydromorphone oral 4, hydromorphone parenteral 20, ketobemidone oral 1, ketobemidone parenteral 3, levorphanol oral 7.5, levorphanol parenteral 15, methadone oral 1.5, methadone parenteral 3, oxycodone oral 1.5, oxycodone parenteral 3, oxymorphone rectal 3, oxymorphone parenteral 30, pethidine parenteral 0.4, tapentadol oral 0.4, tramadol oral 0.25, tramadol parenteral 0.3; (3) read the patch strength from the appropriate table. TABLE 2 — for patients who need OPIOID ROTATION or who are CLINICALLY LESS STABLE (oral morphine to transdermal fentanyl ratio approximately 150:1): under 90 mg/day = 12 micrograms/hour; 90-134 = 25; 135-224 = 50; 225-314 = 75; 315-404 = 100; 405-494 = 125; 495-584 = 150; 585-674 = 175; 675-764 = 200; 765-854 = 225; 855-944 = 250; 945-1,034 = 275; 1,035-1,124 = 300 micrograms/hour. TABLE 3 — for patients on a STABLE, WELL-TOLERATED opioid regimen (ratio approximately 100:1): 44 mg/day or less = 12 micrograms/hour; 45-89 = 25; 90-149 = 50; 150-209 = 75; 210-269 = 100; 270-329 = 125; 330-389 = 150; 390-449 = 175; 450-509 = 200; 510-569 = 225; 570-629 = 250; 630-689 = 275; 690-749 = 300 micrograms/hour. The two tables differ by up to 2-fold for the same oral morphine dose — choose the table that matches the patient's stability, which for many elderly patients is Table 2. Tables 1-3 must be used ONLY to convert TO the patch, never from the patch to another opioid, to avoid overestimating the new analgesic dose and causing overdose. OPIOID-NAIVE PATIENTS: the transdermal route is generally NOT recommended; use oral or parenteral immediate-release opioids first and titrate to an analgesic dose equivalent to a 12 or 25 micrograms/hour patch before switching. If the patch is the only appropriate option, only the lowest starting dose (12 micrograms/hour) should be considered with close monitoring — the potential for serious or life-threatening hypoventilation exists even at the lowest dose. TITRATION AND MAINTENANCE: maximum analgesic effect cannot be evaluated before the patch has been worn for 24 hours, so phase out previous analgesia gradually. Titrate in 12 or 25 micrograms/hour steps (supplementary requirement of oral morphine 45/90 mg/day is approximately equivalent to 12/25 micrograms/hour). After a dose increase it may take up to 6 days to reach equilibrium, so wear the higher-dose patch through two 72-hour applications before any further increase. If analgesia is insufficient during the FIRST application only, the patch may be replaced after 48 hours with a patch of the same dose, or the dose increased after 72 hours. If a patch falls off before 72 hours, apply a patch of the same strength to a different site and monitor closely for increased serum concentrations. Patients may need periodic short-acting analgesia for breakthrough pain. If pain control is inadequate, consider hyperalgesia, tolerance and progression of the underlying disease. RENAL AND HEPATIC IMPAIRMENT: observe carefully and individualise the dose; in opioid-naive patients with renal or hepatic impairment treat only if benefits outweigh risks, and then consider only the 12 micrograms/hour dose initially. DISCONTINUATION: replace with other opioids gradually, starting at a low dose and increasing slowly, because fentanyl concentrations fall gradually — serum levels take 20 hours or more to fall by 50%. Taper gradually to prevent withdrawal; long-term patients may need a more gradual taper. Agree treatment duration, goals and an end-of-treatment plan with the patient before starting, and maintain frequent review. MONITORING: patients who have had serious adverse events should be monitored for at least 24 hours after patch removal. STORAGE SAFETY: patches contain an amount of fentanyl that can be fatal, especially to a child — keep out of sight and reach of children both before and after use, and store and dispose of securely. PAEDIATRIC (not a per-kg dose, so not expressed as mg/kg): children aged 16 years and above follow adult dosing; children 2 to 16 years only if already opioid-tolerant on at least 30 mg oral morphine equivalents per day, converted using SPC Table 4 (oral morphine 30-44 mg/day = 12 micrograms/hour; 45-134 mg/day = 25 micrograms/hour), with conversion above 25 micrograms/hour as for adults; the upper back is the preferred site in young children; do not use below 2 years of age; titrate in 12 micrograms/hour steps with intervals of not less than 72 hours; monitor for adverse events including hypoventilation for at least 48 hours after initiation or up-titration. Verify any paediatric use against a children's formulary and specialist pain or palliative care advice.