Fentanyl (IV — Anaesthesia/ICU)

Source: Fentanyl 50 microgram/ml Injection SPC. The dose must be individualised according to age, body weight, physical status, underlying pathological condition, use of other drugs and the type of surgery and anaesthesia. Give only in an environment where the airway can be controlled and by personnel who can control the airway. To avoid bradycardia it is recommended to give a small intravenous dose of an anticholinergic just before anaesthetic induction. PREMEDICATION: 1-2 ml fentanyl (i.e. of the 50 microgram/ml injection) intramuscularly 45 minutes before induction of anaesthesia. In unpremedicated adults, 2 ml intravenously may be expected to provide sufficient analgesia for 10-20 minutes in surgical procedures involving low pain intensity; 10 ml injected as a bolus gives analgesia lasting about one hour, sufficient for moderately painful procedures. A dose of 50 micrograms/kg will provide intense analgesia for some four to six hours for intensely stimulating surgery. INFUSION (exact units as stated in the SPC): in ventilated patients a loading dose may be given as a fast infusion of approximately 1 microgram/kg/min for the first 10 minutes, followed by an infusion of approximately 0.1 micrograms/kg/min; alternatively the loading dose may be given as a bolus. Infusion rates should be titrated to individual patient response and lower infusion rates may be adequate. Unless post-operative ventilation is planned, the infusion should be terminated about 40 minutes before the end of surgery. Lower infusion rates, e.g. 0.05-0.08 micrograms/kg/minute, are necessary if spontaneous ventilation is to be maintained. Higher infusion rates (up to 3 micrograms/kg/minute) have been used in cardiac surgery. ELDERLY/DEBILITATED: the initial dose should be reduced in patients over 65 years and in debilitated patients; the effect of the initial dose should be taken into account when determining supplemental doses. OBESE PATIENTS: risk of overdosing if the dose is calculated on body weight — calculate dosage according to estimated lean body mass. Chemically incompatible with the induction agents pentobarbital sodium, thiopentone and methohexitone (wide pH differences). Before starting opioid treatment, discuss a strategy for ending treatment with the patient to minimise the risk of addiction and drug withdrawal syndrome.

dosePerKg is left null because the SPC states a RANGE, not a single value. Children aged 2 to 11 years — spontaneous respiration: initial 1-3 micrograms/kg, supplemental 1-1.25 micrograms/kg; assisted ventilation: initial 1-3 micrograms/kg, supplemental 1-1.25 micrograms/kg. Children aged 12 to 17 years: follow adult dosage. Techniques involving analgesia in a spontaneously breathing child should only be used as part of an anaesthetic technique, or as part of a sedation/analgesia technique with experienced personnel, in an environment that can manage sudden chest wall rigidity requiring intubation or apnoea requiring airway support. US labelling adds that safety and efficacy in paediatric patients under two years of age has not been established.