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BackFentanyl Data - Uses, Dosage, Drug class, Brand name, Warnings, etc
| Pharmacology | Fentanyl is a phenylpiperidine opioid agonist with predominant effects on the mu opioid receptor, about 50–100 times more potent as an analgesic than morphine. Related compounds include sufentanil (5–7 times more potent than fentanyl), alfentanil (less potent but faster-acting with shorter duration), and remifentanil (more potent and extremely short-acting due to rapid ester hydrolysis). | ||||||||||||||||||||||||||
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| Administration and Adult Dosage |
- IV patient-controlled analgesia (PCA): 20–100 µg per activation with 3–10-min lockout period, titrated to patient response - Epidural for analgesia: 25–150 µg as intermittent bolus or 25–150 µg/hr as continuous infusion, titrated to patient response - Transdermal for analgesia: Calculate 24-hr analgesic requirement, convert to equivalent oral morphine dose (see Opioid Analgesics Comparison Chart), and use the following table:
- IV for anesthesia: Loading 4–20 µg/kg, maintenance 2–10 µg/kg/hr, additional bolus 25–100 µg - IV for postoperative pain: 50–100 µg every 1–2 hr as needed - Lozenge (Oralet) for anesthesia premedication/conscious sedation: 5 µg/kg, maximum 400 µg - Lozenge (Actiq) for breakthrough cancer pain: Initial 200 µg in patients on >60 mg/day oral morphine or >50 µg/hr transdermal fentanyl; re-administer after 15 min if needed, maximum 2 units per episode during titration, limit to ≤4 units/day |
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| Special Populations - Pediatric Dosage |
- IV for sedation in neonates: 9–20 µg/kg/hr; tolerance limits prolonged use - IV for anesthesia (2–12 yr): 2–3 µg/kg initially, followed by 1–5 µg/kg/hr - Lozenge (Oralet) for premedication/conscious sedation: <15 kg contraindicated; ≥15 kg, 5–15 µg/kg, maximum 400 µg |
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| Special Populations - Geriatric Dosage |
- Lozenge (Oralet) for premedication/conscious sedation (>65 yr): 2.5–5 µg/kg, maximum 400 µg - Increased sensitivity due to altered pharmacodynamics |
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| Other Conditions | - In patients with head injury, cardiovascular, pulmonary, or hepatic disease, use lower dosage: 2.5–5 µg/kg, maximum 400 µg | ||||||||||||||||||||||||||
| Dosage Forms |
- Injection: 50 µg/mL - Sustained-Release Patch: 25, 50, 75, 100 µg/hr - Lozenge for anesthesia (Oralet): 100, 200, 300, 400 µg - Lozenge for breakthrough cancer pain (Actiq): 200, 400, 600, 800, 1200, 1600 µg |
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| Patient Instructions |
- Take as directed; do not exceed recommended dosage - May cause drowsiness; avoid driving or operating machinery until effects are known - Avoid alcohol and other CNS depressants - Report severe constipation, difficulty breathing, or confusion to your physician - Fentanyl Actiq: Limit to ≤4 units/day once effective dosage is determined |
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| Missed Doses |
- If using transdermal patch, apply a missed patch as soon as remembered; do not double the dose - For other forms, consult healthcare provider for guidance |
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| Pharmacokinetics - Onset and Duration |
- IM onset: 7–15 min; duration 1–2 hr - Epidural onset: 5 min; duration 4–6 hr - Transdermal onset: 6–8 hr; peak 24–72 hr; duration 72 hr per application |
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| Pharmacokinetics - Serum Levels |
- Analgesia: 1–3 µg/L (3–9 nmol/L) - Balanced anesthesia: 6–20 µg/L (18–60 nmol/L) |
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| Pharmacokinetics - Fate |
- Bioavailability: Lozenge 52%; transdermal 92% absorbed, ~30% systemic - Protein Binding: 84 ± 2% - Metabolism: Primarily hepatic to norfentanyl and other inactive metabolites - Distribution: Vd = 4 ± 0.4 L/kg - Clearance: Cl = 0.78 ± 0.12 L/hr/kg; decreased in elderly, increased in neonates/children - Excretion: <10% unchanged in urine - Pharmacokinetics unchanged in renal insufficiency or compensated hepatic cirrhosis |
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| Pharmacokinetics - t¹⁄₂ |
- Elimination half-life: 6.1 ± 2 hr; 7.1–11 hr during cardiopulmonary bypass surgery - >17 hr for serum levels to fall by half after transdermal patch removal |
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| Adverse Reactions & Side Effects |
- Sedation, dizziness, nausea, vomiting, constipation, respiratory depression, pruritus - Unlike other opioids, fentanyl and related compounds (alfentanil, remifentanil, sufentanil) do not cause histamine release, preferable for cardiovascular stability - PCA fentanyl causes less postoperative cognitive depression in elderly than PCA morphine - Withdrawal reactions likely in neonates/infants with total dosage >2.5 mg/kg or infusion >9 days |
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| Contraindications |
- Transdermal patch: Acute or postoperative pain, outpatient surgery, patients <12 yr or <50 kg, pain manageable by conventional analgesics, doses >25 µg/hr at therapy initiation - Oralet: Management of acute or chronic pain - Actiq: Management of acute or postoperative pain - Hypersensitivity to fentanyl or other opioids |
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| Precautions & Warnings |
- Use with caution in patients with respiratory disease, head injury, increased intracranial pressure, or hepatic impairment - Risk of respiratory depression; requires close monitoring - Transdermal patches retain 28–84% drug after 3 days, posing lethal risk (1036 µg for 70-kg individual) - Do not cut transdermal patches; use impermeable material to reduce dosage if needed |
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| Drug Interactions |
- CNS depressants (e.g., barbiturates, anesthetics, narcotics, tranquilizers) and ritonavir (via CYP2D6 inhibition) potentiate fentanyl effects - Carbamazepine may decrease fentanyl effect during anesthesia |
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| Parameters to Monitor |
- Monitor vital signs and pain ratings routinely - Assess for respiratory depression and sedation |
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| Class and Drug Brand Name |
- Class: Opioids - Brand Names: Duragesic, Fentanyl Oralet, Sublimaze, Actiq, Various |
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| Notes |
- Epidural administration not superior to IV during surgery - Transdermal fentanyl unsuitable for rapidly changing pain due to slow titratability - Causes less constipation than sustained-release morphine in cancer pain - IV route preferred post-major surgery for titrated bolus or continuous administration; requires close monitoring due to respiratory depression risk |
References
Hand of Clinical Drug Data