No

Analgesic, Narcotic

Analgesic adjunct given by continuous infusion or in incremental doses in maintenance of anesthesia with barbiturate or N₂O or a primary anesthetic agent for the induction of anesthesia in patients undergoing general surgery in which endotracheal intubation and mechanical ventilation are required

C-II

C

Hypersensitivity to alfentanil hydrochloride or narcotics; increased intracranial pressure, severe respiratory depression

Drug dependence, head injury, acute asthma and respiratory conditions; hypotension has occurred in neonates with respiratory distress syndrome; use caution when administering to patients with bradyarrhythmias; rapid I.V. infusion may result in skeletal muscle and chest wall rigidity impaired ventilation respiratory distress/arrest; inject slowly over 3-5 minutes; nondepolarizing skeletal muscle relaxant may be required. Alfentanil may produce more hypotension compared to fentanyl, therefore, be sure to administer slowly and ensure patient has adequate hydration.

>10%:

Cardiovascular: Bradycardia, peripheral vasodilation

Central nervous system: Drowsiness, sedation, increased intracranial pressure

Gastrointestinal: Nausea, vomiting, constipation

Endocrine & metabolic: Antidiuretic hormone release

Ocular: Miosis

1% to 10%:

Cardiovascular: Cardiac arrhythmias, orthostatic hypotension

Central nervous system: Confusion, CNS depression

Ocular: Blurred vision

<1%: Convulsions, mental depression, paradoxical CNS excitation or delirium, dizziness, dysesthesia, rash, urticaria, itching, biliary tract spasm, urinary tract spasm, respiratory depression, bronchospasm, laryngospasm, physical and psychological dependence with prolonged use; cold, clammy skin

Symptoms of overdose include miosis, respiratory depression, seizures, CNS depression

Naloxone 2 mg I.V. (0.01 mg/kg for children) with repeat administration as necessary up to a total of 10 mg; may precipitate withdrawal

CYP3A3/4 enzyme substrate

Increased effect: Dextroamphetamine may enhance the analgesic effect of morphine and other opiate agonists

Increased toxicity: CNS depressants (eg, benzodiazepines, barbiturates, phenothiazines, tricyclic antidepressants), erythromycin, reserpine, beta-blockers

Dilute in D₅W, NS, or LR

Binds with stereospecific receptors at many sites within the CNS, increases pain threshold, alters pain perception, inhibits ascending pain pathways; is an ultra short-acting narcotic

Onset of action: Rapid

Duration: 30-60 minutes (dose dependent)

Distribution: V_d: Newborns, premature: 1 L/kg; Children: 0.163-0.48 L/kg; Adults: 0.46 L/kg

Half-life, elimination: Newborns, premature: 5.33-8.75 hours; Children: 40-60 minutes; Adults: 83-97 minutes

Doses should be titrated to appropriate effects; wide range of doses is dependent upon desired degree of analgesia/anesthesia

Adults: Dose should be based on ideal body weight as follows:

For incremental injection in anesthesia of less than or equal to 30 minutes:

Initial dose (induction period): 8-20 mcg/kg

Maintenance period (increments/infusion): 3-5 mcg/kg or 0.5-1 mcg/kg/minute

Total dose: 8-40 mcg/kg

Appropriate effects: Spontaneously breathing or assisted ventilation when required

For incremental injection in anesthesia of 30-60 minutes:

Initial dose (induction period): 20-50 mcg/kg

Maintenance period (increments/infusion): 5-15 mcg/kg

Total dose: Up to 75 mcg/kg

Appropriate effects: Assisted or controlled ventilation required. Attenuation of response to laryngoscopy and intubation.

For continuous infusion >45 minutes:

Initial dose (induction period): 50-75 mcg/kg

Maintenance period (increments/infusion): 0.5-3 mcg/kg/minute; average infusion rate: 1-1.5 mcg/kg/minute

Total dose: Dependent on duration of procedure

Appropriate effects: Assisted or controlled ventilation required. Some attenuation of response to intubation and incision, with intraoperative stability.

For anesthetic induction >45 minutes:

Initial dose (induction period): 130-245 mcg/kg

Maintenance period (increments/infusion): 0.5-1.5 mcg/kg/minute or general anesthetic

Total dose: Dependent on duration of procedure

Appropriate effects: Assisted or controlled ventilation required. Administer slowly (over 3 minutes). Concentration of inhalation agents reduced by 30% to 50% for initial hour.

Administer I.V. slowly over 3-5 minutes or by I.V. continuous infusion

Respiratory rate, blood pressure, heart rate

100-340 ng/mL (depending upon procedure)

Sedation is common, may see depression or confusion, rarely may cause seizures or delirium

CNS depressant and beta-blockers may increase toxicity; phenothiazines may antagonize analgesic effect

No information available to require special precautions

Erythromycin inhibits the liver metabolism of alfentanil resulting in increased sedation and prolonged respiratory depression

Monitor patient for CNS, respiratory depression, and urticaria

Injection, preservative free, as hydrochloride: 500 mcg/mL (2 mL, 5 mL, 10 mL, 20 mL)

Bartkowski RR and McDonnell TE, "Prolonged Alfentanil Effect Following Erythromycin Administration," Anesthesiology, 1990, 73(3):566-8.

Bartkowski RR, Goldberg ME, Larijani GE, et al, "Inhibition of Alfentanil Metabolism by Erythromycin," Clin Pharmacol Ther, 1989, 46(1):99-102.

Bodenham A and Park GR, "Alfentanil Infusions in Patients Requiring Intensive Care," Clin Pharmacokinet, 1988, 15(4):216-26.

Davis PJ, Killian A, Stiller RL, et al, "Pharmacokinetics of Alfentanil in Newborn Premature Infants and Older Children," Dev Pharmacol Ther, 1989, 13(1):21-7.

Kirkham SR and Pugh R, "Opioid Analgesia in Uraemic Patients," Lancet, 1995, 345(8958):1185.

Marlow N, Weindling AM, Van Peer A, et al, "Alfentanil Pharmacokinetics in Preterm Infants," Arch Dis Child, 1990, 65(4 Spec No):349-51.

Meistelman C, Saint-Maurice C, Lepaul M, et al, "A Comparison of Alfentanil Pharmacokinetics in Children and Adults," Anesthesiology, 1987, 66(1):13-6.

Pokela ML, Ryhanen PT, Koivisto ME, et al, "Alfentanil-Induced Rigidity in Newborn Infants," Anesth Analg, 1992, 75(2):252-7.

Scholz J, Steinfath M, and Schulz M, "Clinical Pharmacokinetics of Alfentanil, Fentanyl, and Sufentanil. An Update," Clin Pharmacokinet, 1996, 31(4):275-92.