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Opioid Analgesic — Transdermal Patch Pregnancy: Use only if clearly necessary — neonatal opioid withdrawal syndrome; neonatal respiratory depression; if used near term, have naloxone available for neonatal resuscitation

Fentanyl Transdermal Patch (Elderly Chronic Pain)

Brand names: Durogesic DTrans, Matrifen, Mezolar

Adult dose

Dose: Starting dose in opioid-naive elderly: 12 mcg/hour patch (change every 72 hours); titrate in 12–25 mcg/hour increments every 72 hours; standard doses 12–100 mcg/hour
Route: Transdermal (apply to flat, non-irritated, non-hairy skin — chest, back, upper arm)
Frequency: Every 72 hours (change patch)
Max: No absolute maximum — titrate to pain control; high doses require specialist review
Advantages in elderly: no tablets to swallow (dysphagia), no GI absorption variability, consistent plasma levels avoiding peaks/troughs, less GI side effects than oral opioids. Disadvantages: 12–24 hour lag time to peak effect; cannot rapidly titrate; fever increases absorption 30%. MUST NOT cut patches.

Paediatric dose

Route:
Frequency: Every 72 hours
Max: Specialist palliative/pain management guidance only
Not licensed under 2 years. Children ≥2 years: palliative/specialist pain service only; opioid-tolerant patients only (not opioid-naive). BNFc guidance.

Dose adjustments

Renal

Preferred opioid in renal failure — fentanyl has no active metabolites that accumulate (unlike morphine with M6G; or oxycodone with oxymorphone). Standard dose; monitor closely for toxicity.

Hepatic

Caution in severe hepatic impairment — reduced first-pass metabolism not relevant (transdermal), but hepatic clearance of systemic fentanyl reduced — start low, monitor closely.

Clinical pearls

  • Renal failure advantage: fentanyl is the opioid of choice in significant renal impairment (eGFR <30) — metabolised to inactive compounds (norfentanyl), no nephrotoxic accumulation unlike morphine (M6G accumulates → prolonged sedation/respiratory depression) or codeine (morphine accumulates); SIGN 106 and BNF endorse fentanyl transdermal in CKD
  • Fever significantly increases absorption: body temperature above 40°C increases fentanyl release by approximately 33% — risk of respiratory depression; advise patients to call for advice if febrile; consider patch dose reduction during febrile illness
  • Patch disposal: patients must fold used patch with sticky sides together and dispose of in the original sachet — significant fentanyl remains in used patches; child safety and environmental hazard; MHRA guidance on safe disposal

Contraindications

  • Opioid-naive patients requiring rapid titration (delayed onset — not suitable for acute pain)
  • Acute or post-operative pain (unpredictable absorption and inability to rapidly reverse)
  • Raised intracranial pressure (caution — CO2 retention from respiratory depression worsens ICP)
  • Severe respiratory disease (COPD, sleep apnoea — significant risk)

Side effects

  • Respiratory depression (potentially fatal — particularly in opioid-naive, concurrent CNS depressants)
  • Constipation (less than oral opioids but still significant in elderly)
  • Nausea and vomiting
  • Skin reactions at patch site (erythema, rash)
  • Cognitive impairment and sedation
  • Falls (opioid-related — elderly risk)
  • Hypogonadism and androgen deficiency (long-term)
  • Increased absorption in fever (temperature >40°C increases fentanyl release 33%)

Interactions

  • CNS depressants (benzodiazepines, pregabalin, gabapentin, alcohol — respiratory depression — MHRA 2020 warning)
  • CYP3A4 inhibitors (fluconazole, ketoconazole, ritonavir — increase fentanyl plasma levels significantly — reduce patch dose)
  • MAOIs (avoid — severe serotonergic and hyperpyrexic reactions)
  • 5-HT affecting drugs (tramadol, SSRIs — serotonin syndrome risk at high doses)

Monitoring

  • Respiratory rate and SpO2 (especially when initiating or increasing dose)
  • Sedation score
  • Pain scores (NRS/VAS)
  • Patch site inspection (rotation required — same site only after 7 days)
  • Constipation (co-prescribe laxative prophylactically)
  • Falls risk assessment

Reference: BNFc; BNF 90; SIGN 106 (Control of Pain in Adults with Cancer); NICE NG215 (Chronic Pain in Adults); MHRA SPC Durogesic; BNFc; MHRA Drug Safety Update 2020 (opioid + CNS depressants). Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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