Fentanyl (Transdermal Patch)

EQUIANALGESIC CONVERSION (adults): (1) calculate the 24-hour dose in mg/day of the opioid currently used; (2) convert to the equianalgesic 24-hour ORAL MORPHINE dose using the SPC multiplication factors (oral morphine 1, parenteral morphine 3, oral oxycodone 1.5, parenteral oxycodone 3, oral hydromorphone 4, parenteral hydromorphone 20, oral codeine 0.15, parenteral codeine 0.23, oral tramadol 0.25, parenteral tramadol 0.3, oral methadone 1.5, parenteral methadone 3, oral tapentadol 0.4, sublingual buprenorphine 75, parenteral buprenorphine 100, parenteral fentanyl 300, oral diamorphine 0.5, parenteral diamorphine 6, parenteral pethidine 0.4, oral levorphanol 7.5, parenteral levorphanol 15, oral ketobemidone 1, parenteral ketobemidone 3, rectal oxymorphone 3, parenteral oxymorphone 30); (3) read the patch strength from SPC Table 2 for patients needing opioid rotation or who are less clinically 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; 945-1034 = 275; 1035-1124 = 300), or from SPC 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). These tables must be used ONLY to convert TO Durogesic DTrans, never from it to another opioid, to avoid overestimating the new analgesic dose and causing overdose. ONSET AND TITRATION: the maximum analgesic effect cannot be evaluated before the patch has been worn for 24 hours, so previous analgesic therapy should be phased out gradually after the first application. Titrate in 12 or 25 micrograms/hour increments; after an increase it may take up to 6 days to reach equilibrium, so wear the higher-strength patch through two 72-hour applications before increasing again. Supplementary requirement guide: oral morphine 45/90 mg/day is approximately equivalent to 12/25 micrograms/hour. 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 skin site and monitor closely (serum concentrations may increase). DISCONTINUATION: replacement with other opioids should be gradual, starting at a low dose and increasing slowly, because fentanyl concentrations fall gradually — serum concentrations may take 20 hours or more to fall by 50%. Taper to prevent serious withdrawal symptoms and uncontrolled pain. ELDERLY, RENAL AND HEPATIC IMPAIRMENT: observe carefully and individualise the dose; in opioid-naive patients in these groups treat only if benefits outweigh risks, and then only the 12 micrograms/hour dosage should be considered for initial treatment. PAEDIATRIC: children aged 16 years and above follow the adult dosage. Children 2 to 16 years — give ONLY to opioid-tolerant children already receiving at least 30 mg oral morphine equivalents per day; convert using SPC Table 4 (oral 24-hour morphine 30-44 mg/day = 12 micrograms/hour; 45-134 mg/day = 25 micrograms/hour), with conversion above 25 micrograms/hour the same as for adults. Do NOT use in children aged under 2 years (safety and efficacy not established). In children, give the previous regular analgesic dose during the first 12 hours after switching, then provide analgesia on clinical need for the next 12 hours; monitor for adverse events including hypoventilation for at least 48 hours after initiation or up-titration; do not increase the dose at intervals of less than 72 hours, and adjust in 12 micrograms/hour steps. Paediatric opioid dosing is safety-critical — verify against a children's formulary. SAFETY: patients and carers must be told that each patch contains an amount of active substance that can be FATAL, especially to a child, and must keep all patches out of the sight and reach of children both before and after use, and stored securely. Monitor patients who have had serious adverse events for at least 24 hours after patch removal, as serum fentanyl concentrations decline gradually (reduced by about 50% 20 to 27 hours later). US SOURCE NOTE: the openFDA record in this bundle is Fentanyl CITRATE INJECTION (an intravenous/intramuscular anaesthetic product) — a different route and product; none of its figures have been used on this page.