fentanyl (parenteral)

High Alert

Analgesic supplement to general anesthesia; usually with other agents (ultra–short-acting barbiturates, neuromuscular blocking agents, and inhalation anesthetics) to produce balanced anesthesia.
Induction/maintenance of anesthesia (in combination with oxygen or oxygen/nitrous oxide and a neuromuscular blocking agent).
Neuroleptanalgesia/neuroleptanesthesia (with or without nitrous oxide).
Supplement to regional/local anesthesia.
Preoperative and postoperative analgesia.

Unlabeled Use:

Continuous IV infusion as part of patient-controlled analgesia.

Action ⬆ ⬇

Binds to opiate receptors in the CNS, altering the response to and perception of pain.
Produces CNS depression.

Therapeutic effects:

Supplement in anesthesia.
Decreased pain.

Pharmacokinetics ⬆ ⬇

Absorption: Well absorbed after IM administration. IV administration results in complete bioavailability.

Distribution: Extensively distributed to CNS and tissues.

Metabolism/Excretion: Primarily metabolized by the liver via the CYP3A4 isoenzyme; 10–25% excreted unchanged by the kidneys.

Half-Life: Children: Bolus dose—2.4 hr, long-term continuous infusion—11–36 hr; Adults: 2–4 hr (↑ after cardiopulmonary bypass and in geriatric patients).

Time/Action Profile ⬆ ⬇

(analgesia*)

ROUTE	ONSET	PEAK	DURATION
IM	7–15 min	20–30 min	1–2 hr
IV	1–2 min	3–5 min	0.5–1 hr

*Respiratory depression may last longer than analgesia.

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity; cross-sensitivity among agents may occur;
Known intolerance;
Concurrent use of MAO inhibitors.

Use Cautiously in:

Diabetes;
Severe renal impairment;
Severe hepatic impairment;
Severe pulmonary disease;
CNS tumors;
↑intracranial pressure;
Head trauma;
Adrenal insufficiency;
Undiagnosed abdominal pain;
Hypothyroidism;
Alcoholism;
Cardiac disease (arrhythmias);
OB: Use during pregnancy only if potential maternal benefit justifies potential fetal risk. Chronic maternal treatment with opioids during pregnancy may result in neonatal abstinence syndrome;
Lactation: Use while breastfeeding only if potential maternal benefit justifies potential risk to infant (may cause infant sedation and/or respiratory depression);
Geri: Older adults may be more sensitive to effects and may have an risk of adverse reactions; titrate dosage carefully.

Adv. Reactions/Side Effects ⬆ ⬇

CV: arrhythmias, bradycardia, hypotension

Derm: facial itching

EENT: blurred/double vision

Endo: adrenal insufficiency

GI: biliary spasm, nausea, vomiting

MS: skeletal and thoracic muscle rigidity (with rapid IV infusion)

Neuro: confusion, paradoxical excitation/delirium, postoperative drowsiness

Resp: allergic bronchospasm, APNEA, LARYNGOSPASM, RESPIRATORY DEPRESSION (INCLUDING CENTRAL SLEEP APNEA AND SLEEP-RELATED HYPOXEMIA)

Interactions ⬆ ⬇

Drug-drug:

Concurrent use or within previous 14 days of MAO inhibitors may produce unpredictable, potentially fatal reactions and is contraindicated.
CYP3A4 inhibitors, including ritonavir, ketoconazole, itraconazole, clarithromycin, nelfinavir, nefazodone, diltiazem, aprepitant, fluconazole, fosamprenavir, verapamil, and erythromycin, may ↑ levels and ↑ risk of CNS and respiratory depression.
CYP3A4 inducers, including barbiturates, carbamazepine, efavirenz, corticosteroids, modafinil, nevirapine, oxcarbazepine, phenobarbital, phenytoin, rifabutin, or rifampin, may ↓ levels and analgesia; if inducers are discontinued or dosage ↓, patients should be monitored for signs of opioid toxicity and necessary dose adjustments should be made.
Use with benzodiazepines or other CNS depressants, including other opioids, non-benzodiazepine sedative/hypnotics, anxiolytics, general anesthetics, muscle relaxants, antipsychotics, and alcohol, may cause profound sedation, respiratory depression, coma, and death; reserve concurrent use for when alternative treatment options are inadequate.
↑risk of hypotension with benzodiazepines.
Nalbuphine or buprenorphine may ↓ analgesia.
Drugs that affect serotonergic neurotransmitter systems, including tricyclic antidepressants, SSRIs, SNRIs, MAO inhibitors, TCAs, tramadol, trazodone, mirtazapine, 5–HT3 receptor antagonists, linezolid, methylene blue, and triptans, ↑ risk of serotonin syndrome.

Grapefruit juice may ↑ levels and the risk of respiratory and CNS depression.

Route/Dosage ⬆ ⬇

Preoperative Use

IM IV (Adults and Children >12 yr): 50–100 mcg 30–60 min before surgery.

Adjunct to General Anesthesia

IM IV (Adults and Children >12 yr): Low dose–minor surgery: 2 mcg/kg. Moderate dose–major surgery: 2–20 mcg/kg. High dose–major surgery: 20–50 mcg/kg.

Adjunct to Regional Anesthesia

IM IV (Adults and Children >12 yr): 50–100 mcg.

Postoperative Use (Recovery Room)

IM IV (Adults and Children >12 yr): 50–100 mcg; may repeat in 1–2 hr.

General Anesthesia

IV (Adults and Children >12 yr): 50–100 mcg/kg (up to 150 mcg/kg).
IV (Children 1–12 yr): 2–3 mcg/kg.

Sedation/Analgesia

IV (Adults and Children >12 yr): 0.5–1 mcg/kg/dose, may repeat after 30–60 min.
IV (Children 1–12 yr): Bolus: 1–2 mcg/kg/dose, may repeat at 30–60 min intervals. Continuous infusion: 1–5 mcg/kg/hr following bolus dose.
IV (Neonates ): Bolus: 0.5–3 mcg/kg/dose. Continuous infusion: 0.5–2 mcg/kg/hr following bolus dose. Continuous infusion during ECMO: 5–10 mcg/kg bolus followed by 1–5 mcg/kg/hr; may require up to 20 mcg/kg/hr after 5 days of therapy.

Availability ⬆ ⬇

(Generic available)

Solution for injection: 50 mcg/mL

Assessment ⬆ ⬇

Assess type, location, and intensity of pain prior to and 30 min following IM and 5 min (peak) following IV administration. When titrating opioid doses, increases of 25–50% should be administered until there is either a 50% reduction in the patient's pain rating on a numerical or visual analogue scale or the patient reports satisfactory pain relief.
Monitor respiratory rate and BP frequently during therapy, especially when starting therapy or when given with other drugs that depress respiration. May cause sleep-related breathing disorders (central sleep apnea, sleep-related hypoxemia). Report significant changes immediately. The respiratory depressant effects of fentanyl may last longer than the analgesic effects. Initial doses of other opioids should be reduced by 25–33% of the usually recommended dose. Monitor closely.
Geri: Opioids have been associated with increased risk of falls in older adults. Assess risk and implement fall prevention strategies.
Assess type, location, and intensity of pain before and 30 min after IM administration or 3–5 min after IV administration when fentanyl is used to treat pain.
Assess risk for opioid addiction, abuse, or misuse prior to administration.

Lab Test Considerations:

May cause ↑ serum amylase and lipase concentrations.

Toxicity and Overdose:

Symptoms of toxicity include respiratory depression, hypotension, arrhythmias, bradycardia, and asystole. Atropine may be used to treat bradycardia. If respiratory depression persists after surgery, prolonged mechanical ventilation may be required. If an opioid antagonist is required to reverse respiratory depression or coma, naloxone is the antidote. Dilute the 0.4-mg ampule of naloxone in 10 mL of 0.9% NaCl and administer 0.5 mL (0.02 mg) by IV push every 2 min. Pedi: For children and patients weighing 40 kg, dilute 0.1 mg of naloxone in 10 mL of 0.9% NaCl for a concentration of 10 mcg/mL and administer 0.5 mcg/kg every 2 min. Titrate dose to avoid withdrawal, seizures, and severe pain. Administration of naloxone in these circumstances, especially in cardiac patients, has resulted in hypertension and tachycardia, occasionally causing left ventricular failure and pulmonary edema.

Implementation ⬆ ⬇

Accidental overdosage of opioid analgesics has resulted in fatalities. Before administering, clarify all ambiguous orders; have second practitioner independently check original order, dose calculations, route of administration, and infusion pump programming.
Do not confuse fentanyl with sufentanil.
Benzodiazepines may be administered before or after administration of fentanyl to reduce the induction dose requirements, decrease the time to loss of consciousness, and produce amnesia. This combination may also increase the risk of hypotension and respiratory depression.
Explain therapeutic value of medication prior to administration to enhance the analgesic effect.
- Regularly administered doses may be more effective than prn administration. Analgesic is more effective if given before pain becomes severe.
- Coadministration with nonopioid analgesics may have additive analgesic effects and permit lower opioid doses.
- Medication should be discontinued gradually after long-term use to prevent withdrawal symptoms.
May cause muscle rigidity, particularly involving muscles of respiration; effects are related to the dose and speed of injection. Effects can be reduced by: 1) administration of up to 1/4 of the full paralyzing dose of a non-depolarizing neuromuscular blocking agent just prior to administration of fentanyl; 2) administration of a full paralyzing dose of a neuromuscular blocking agent following loss of eyelash reflex when fentanyl is used in anesthetic doses titrated by slow intravenous infusion; or, 3) simultaneous administration of fentanyl and a full paralyzing dose of a neuromuscular blocking agent when fentanyl is used in rapidly administered anesthetic doses.

IV Administration:

Diluent: Administer undiluted.Concentration: 50 mcg/mL.
Rate: Inject slowly over 1–3 min. Administer doses >5 mcg/kg over 5–10 min. Slow IV administration may reduce the incidence and severity of muscle rigidity, bradycardia, or hypotension. Neuromuscular blocking agents may be administered concurrently to decrease chest wall muscle rigidity.
Intermittent Infusion: Diluent: May be diluted in D5W or 0.9% NaCl.Concentration: Up to 50 mcg/mL.

Patient/Family Teaching ⬆ ⬇

Discuss the use of anesthetic agents and the sensations to expect with the patient before surgery.
Instruct patient on how and when to ask for pain medication. Explain pain assessment scale to patient.
Advise patient to notify health care professional if pain control is not adequate or if side effects occur.
Caution patient to change positions slowly to minimize orthostatic hypotension. Geri: Older adults may be at a greater risk for orthostatic hypotension and, consequently, falls. Teach patient to take precautions until drug effects have completely resolved.
Medication causes dizziness and drowsiness. Advise patient to call for assistance during ambulation and transfer, and to avoid driving or other activities requiring alertness for 24 hr after administration during outpatient surgery.
Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and consult health care professional before taking any new medications.
Encourage patient to turn, cough, and breathe deeply every 2 hr to prevent atelectasis.
Instruct patient to avoid alcohol or other CNS depressants for 24 hr after administration for outpatient surgery.
Rep: Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected, or if breastfeeding. Inform patient of potential for neonatal opioid withdrawal syndrome with prolonged use during pregnancy. Monitor neonate for signs and symptoms of withdrawal symptoms (irritability, hyperactivity and abnormal sleep pattern, high pitched cry, tremor, vomiting, diarrhea, and/or failure to gain weight); usually occur the first days after birth. Monitor infants exposed to fentanyl through breast milk for excess sedation and respiratory depression.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇