Generic Name

Fentanyl Citrate

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Classification

FDA Approved Indications

• Severe pain management, including breakthrough pain in cancer patients
• Anesthesia adjunct for surgical procedures

Mechanism of Action

Fentanyl is a potent synthetic opioid that binds primarily to the mu-opioid receptors in the central nervous system, producing analgesia by inhibiting ascending pain pathways and altering the perception of and response to pain.

Dosage and Administration

Adult: Dose varies based on formulation and patient need; for example, transdermal patches start at 25 mcg/hour and titrate as needed; transmucosal formulations adjust dose based on onset and pain severity.

Pediatric: Use with caution; specific pediatric dosing depends on formulation and patient weight/age, typically under strict medical supervision.

Geriatric: Start at lower doses due to increased sensitivity and risk of adverse effects.

Renal Impairment: Use with caution; may require dose adjustments depending on severity.

Hepatic Impairment: Use with caution; hepatic metabolism influences dosing.

Pharmacokinetics

Absorption: Rapid absorption depending on the route; transmucosal routes have quick onset.

Distribution: Widely distributed in tissues, crosses blood-brain barrier.

Metabolism: Primarily hepatic via CYP3A4 enzyme into inactive metabolites.

Excretion: Renally excreted, mostly as metabolites.

Half Life: Approximately 2-4 hours for plasma half-life; transdermal patches provide a slow release over 72 hours.

Contraindications

• Known hypersensitivity to fentanyl or other opioids.
• Respiratory depression, including severe respiratory compromise.

Precautions

• Use caution in patients with head injury, increased intracranial pressure, or impaired pulmonary function.
• Risk of addiction, abuse, and misuse—limit access and monitor usage.
• Pregnancy Category C; use only if clearly needed. Risks to fetus have been reported.
• Lactation: Fentanyl is excreted in breast milk; breastfeeding is generally discouraged during treatment.

Adverse Reactions - Common

• Respiratory depression (Serious, life-threatening, if overdose occurs)
• Nausea (Common)
• Constipation (Common)
• Sedation (Common)
• Dizziness (Common)

Adverse Reactions - Serious

• Bradycardia or tachycardia (Serious)
• Hypotension or hypertension (Serious)
• Seizures (Serious)
• Allergic reactions, including rash, itching, swelling, difficulty breathing (Serious)

Drug-Drug Interactions

• CNS depressants (benzodiazepines, alcohol), other opioids, MAO inhibitors, CYP3A4 inhibitors and inducers

Drug-Food Interactions

• Avoid alcohol and concomitant use of other sedatives.

Drug-Herb Interactions

• Caution with herbs that affect CYP3A4 (e.g., St. John's Wort).

Nursing Implications

Patient/Family Teaching

• Instruct on proper use and storage of medication.
• Warn about respiratory depression and signs of overdose.
• Advise against alcohol and sedatives during treatment.
• Educate on the importance of adhering to prescribed dosages.

Special Considerations

Black Box Warnings:

• Risk of addiction, overdose, and death, especially with inappropriate use.

Genetic Factors: Genetic variations in CYP3A4 can influence fentanyl metabolism.

Lab Test Interference: May affect laboratory tests for certain enzymes or markers.

Overdose Management

Signs/Symptoms: Respiratory depression, extreme drowsiness, unconsciousness, miosis, cyanosis.

Treatment: Administer naloxone promptly; provide supportive airway and ventilation; establish IV access and monitor vital signs.

Storage and Handling

Storage: Store at controlled room temperature, away from light and moisture.

Stability: Stable under recommended conditions; check expiration dates regularly.