Dosing and uses of Alfenta, Rapifen (alfentanil)
Adult dosage forms and strengths
injectable solution: Schedule II
- 0.5mg/mL
Dose should be calculated based on ideal body weight
Incremental Injection: Anesthesia <30 Minutes
Induction: 8-20 mcg/kg IV
Maintenance: 3-5 mcg/kg IV increments q5-20min, or 0.5-1 mcg/kg/min IV
Total dose: 8-40 mcg/kg IV
Incremental Injection: Anesthesia 30-60 Minutes
Induction: 20-50 mcg/kg IV
Maintenance: 5-15 mcg/kg IV increments q5-20min
Total dose: Up to 75 mcg/kg IV
Anesthetic Induction: Anesthesia >45 Minutes
Induction: 130-245 mcg/kg IV
Maintenance: 0.5-1.5 mcg/kg/min IV or other general anesthetic
Total dose: depends on duration of operation
Continuous Infusion: For Anesthesia >45 Minutes
Induction: 50-75 mcg/kg IV
Maintenance: 0.5-3 mcg/kg/min IV
Total dose: depends on duration of operation
Postherpetic Neuralgia (Orphan)
Management of postherpetic neuralgia
Orphan indication sponsor
- Cinergen, LLC; 146 Medinah Drive; Blue Bell, PA 19422-3212
HIV-Associated Neuropathy (Orphan)
Treatment of painful HIV-associated neuropathy
Orphan indication sponsor
- Cinergen, LLC; 146 Medinah Drive; Blue Bell, PA 19422-3212
Administration
Total dose: depends on duration of operation
Pediatric dosage forms and strengths
injectable solution: Schedule II
- 0.5mg/mL
Dose should be calculated based on ideal body weight
<12 years
Anesthesia
- Not recommended
>12 years
Incremental Injection: Anesthesia <30 Minutes
- Induction: 8-20 mcg/kg IV
- Maintenance: 3-5 mcg/kg IV increments q5-20min, or 0.5-1 mcg/kg/min IV
- Total dose: 8-40 mcg/kg IV
Incremental Injection: Anesthesia 30-60 Minutes
- Induction: 20-50 mcg/kg IV
- Maintenance: 5-15 mcg/kg IV increments q5-20min
- Total dose: Up to 75 mcg/kg IV
Anesthetic Induction: Anesthesia >45 Minutes
- Induction: 130-245 mcg/kg IV
- Maintenance: 0.5-1.5 mcg/kg/min IV or other general anesthetic
- Total dose: depends on duration of operation
Continuous Infusion: For Anesthesia >45 Minutes
- Induction: 50-75 mcg/kg IV
- Maintenance: 0.5-3 mcg/kg/min IV
- Total dose: depends on duration of operation
Alfenta, Rapifen (alfentanil) adverse (side) effects
>10%
Arrhythmia (14%)
Bradycardia (14%)
Chest wall rigidity (17%)
Hypertension (18%)
Nausea (28%)
Vomiting (18%)
Tachycardia (12%)
1-10%
Apnea (3-9%)
Blurred vision (1-3%)
Dizziness (3-9%)
Hypotension (10%)
Post-op respiratory depression (1-3%)
Skeletal muscle movements (3-9%)
Postoperative sedation (1-3%)
<1%
Sweating, flushing
Warmness of the face/neck/upper thorax
Pruritus
urticaria
Respiratory (undefined)
Respiratory/circulatory depression
Respiratory arrest
Shock
Cardiac arrest
Nervous System (undefined)
Dizziness
Visual disturbances
Mental clouding/depression
Sedation
Coma
Euphoria
Dysphoria
Weakness
Faintness
Agitation
Restlessness
Nervousness
Seizures
GI (undefined)
Nausea
Vomiting
Constipation
Cardiovascular (undefined)
QT-interval prolongation
Severe cardiac arrhythmias
Cardiac arrest
ST segment elevation
VTach
MI
Angina pectoris
Syncope
Genitourinary (undefined)
Urinary retention
Oliguria
Cholinergic (undefined)
Bradycardia
Dry mouth
Palpitation
Tachycardia
Warnings
Contraindications
Hypersensitivity
Increased intracranial pressure
Severe respiratory depresssion
Cautions
Use caution in bradycardia, compromised cardiac reserve, head injury, hypothyroidism, increased ICP, intracranial lesions, renal impairment, respiratory impairment, obesicty, history of drug abuse
Concurrent administration of benzodiazepine or neuromuscular blocker will decrease chest wall rigidity
Skeletal muscle and chest wall rigidity, respiratory distress, or impaired ventilation may occur with rapid infusion (slow injection over 3-5min recommended)
Should be administered by trained individuals
Pregnancy and lactation
Pregnancy category: C
Lactation: use with caution
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Alfenta, Rapifen (alfentanil)
Mechanism of action
Narcotic agonist analgesic; increases pain threshold, inhibits ascending pain pathways, alters pain perception
Pharmacokinetics
Half-life: 5.33-8.75 hr (prematures, newborns); 40-60 min (children); 83-97 min (adults)
Onset: Immediate
Duration: 30-60 min
Vd: 1 L/kg (premature, newborns); 0.163-0.48 L/kg (children); 0.46 L/kg (adults)
Peak Plasma: distributed in decreasing order of concentration into skeletal muscle, kidneys, liver, intestinal tract, lungs, spleen, and brain
Bioavailability: Varies
Metabolism: liver (hepatic P450 enzyme CYP3A4), CNS, kidneys, lungs, and placenta (conjugation with glucuronic acid, hydrolysis, oxidation, N-dealkylation)
Excretion: urine, feces
Administration
IV Compatibilities
Solution: D5W
Syringe: atracurium, midazolam, ondansetron
Y-site: bivalirudin, cisatracurium, dexmedetomidine, etomidate, fenoldopam, gatifloxacin, Hextend, linezolid, propofol, remifentaniL
IV Incompatibilities
Y-site: amphotericin B cholSO4, thiopentaL
IV Preparation
Add 20 mL to 230 mL of diluent for a final concentration of 40 mg/mL
IV Administration
Keep Naloxone and resuscitation equip available
By incremental injection as analgesic adjunct to anesthesia with barbiturate/nitrous oxide/oxygen for short surgical procedures (expected duration <1 hr)
By continuous infusion as a maintenance analgesic with nitrous oxide/oxygen for general surgical procedures
By IV injection in aesthetic doses for anesthesia induction for general surgical procedures with a minimum expected duration of 45 min
By IV inj as the analgesic component for monitored anesthesia care (MAC)
Storage
Protect from light
Store at controlled room temp
