Alfentanil Hydrochloride


  • General anesthetic
  • Opioid analgesic agonist
  • Anesthesia adjunct
  • pH 4 to 6



Adults and pediatric patients 12 years of age and older: Dose must be individualized and titrated to the desired effect in each patient according to body weight, physical status, underlying pathologic condition, use of other drugs, and type and duration of surgical procedure and anesthesia.

Alfentanil Dosing Guidelines for Use During General Anesthesia





Continuous infusion: 0.5-3 mcg/kg/min administered with nitrous oxide/oxygen in patients undergoing general surgery. Following an anesthetic induction dose of alfentanil, infusion rate requirements are reduced by 30%-50% for the first hour of maintenance. Changes in vital signs that indicate a response to surgical stress or lightening of anesthesia may be controlled by increasing the alfentanil to a maximum of 4 mcg/kg/min and/or administration of bolus doses of 7 mcg/kg. If changes are not controlled after three bolus doses given over a 5-minute period, a barbiturate, vasodilator, and/or inhalation agent should be used. Infusion rates should always be adjusted downward in the absence of these signs until there is some response to surgical stimulation. Rather than an increase in infusion rate, 7 mcg/kg bolus doses of alfentanil or a potent inhalation agent should be administered in response to signs of lightening of anesthesia within the last 15 minutes of surgery. Alfentanil infusion should be discontinued at least 10 to 15 minutes before the end of surgery. Discontinue 10 to 15 minutes before end of procedures in general anesthesia. Continue infusion to end of procedure during MAC, then discontinue.


Average dose:

Bradycardia and hypotension may occur shortly after administration. Res�piratory depression caused by alfentanil and/or muscle rigidity may progress to apnea. Agitation, arrhythmias (e.g., bradycardia, tachycardia), blurred vision, bradypnea, chest wall rigidity, dizziness, euphoria, headache, hypercapnia (increased CO2), hypersensitivity reactions (e.g., anaphylaxis, bronchospasm, itching, laryngospasm, urticaria), hypertension, hypotension, muscle rigidity (skeletal muscles including abdomen, chest, pharynx, neck, and extremities), myoclonic movements, nausea, postoperative confusion, respiratory sedation, shivering, skeletal muscle movements, sleepiness, vomiting.


Bradycardia; circulatory depression; cold, clammy skin; dizziness (severe); drowsiness (severe); hypotension; nervousness or restlessness (severe); pinpoint pupils of eyes; respiratory depression; weakness (severe).



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