Adults: Oral
Starting dose: The initial dose of Fentanyl should be 100 mcg.
Re-dosing within a single episode: If one Fentanyl dose doesn't relieve the pain properly during an episode of breakthrough pain, the dose may be repeated once. This can be done 30 minutes after the start of administration, and the same dosage strength should be used.
Increasing the dose: Titration should start with multiples of the 100 mcg Fentanyl tablet. Patients who need to go above 100 mcg can be told to use two 100 mcg tablets, one on each side of the mouth in the buccal cavity. If that doesn't control the breakthrough pain episode, the patient may be told to place two 100 mcg tablets on each side of the mouth in the buccal cavity (four 100 mcg tablets in total). Above 400 mcg, titrate in 200 mcg increments. Using more than 4 tablets at the same time has not been studied, so bear that in mind. It is also important to keep the number of strengths available to patients to a minimum at any time, to prevent confusion and possible overdose. For the same reason, patients should have only one strength of Fentanyl tablet at hand at any one time during titration.
Dosage adjustment: Generally, the Fentanyl dose should be increased when a patient needs more than one dose per breakthrough pain episode for several consecutive episodes.
Injection
Fentanyl injection can be given intravenously, either as a bolus or by infusion, and also by the intramuscular route. The dose should be individualized according to age, body weight, physical status, underlying pathological condition, use of other drugs, and the type of surgery and anesthesia. Doses above 200mcg are for use in anesthesia only.
As a premedicant, 1 to 2 ml of fentanyl may be given intramuscularly 45 minutes before induction of anesthesia. After IV administration in unpremedicated adult patients, 2ml of fentanyl can be expected to give enough analgesia for 10 to 20 minutes in surgical procedures with low pain intensity. A bolus of 10 ml gives analgesia lasting about one hour, which is enough for moderately painful procedures. A dose of 50 mcg/kg gives intense analgesia for some four to six hours, for intensely stimulating surgery.
Fentanyl may also be given as an infusion. In ventilated patients, the loading dose may be given as a fast infusion of approximately 1 mcg/kg/min for the first 10 minutes, followed by an infusion of approximately 0.1 mcg/kg/min. The loading dose may alternatively be given as a bolus. Infusion rates should be titrated to the individual patient's response; lower infusion rates may be adequate. Unless post-operative ventilation is planned, stop the infusion about 40 minutes before the end of surgery. If spontaneous ventilation is to be maintained, lower infusion rates are necessary, e.g. 0.05 to 0.08 mcg/kg/min. Higher infusion rates (up to 3 mcg/kg/min) have been used in cardiac surgery.
Fentanyl is chemically incompatible with the induction agents thiopentone and methohexitone, because their pH is very different.
Use in elderly and debilitated patients: It is wise to reduce the dosage in elderly and debilitated patients. The effect of the initial dose should be taken into account when deciding on supplemental doses.
Transdermal
Intractable chronic pain, adult: The patches deliver fentanyl in doses ranging from 12 to 100 mcg/hr. Doses should be individually titrated based on previous use of opioids.
Opioid-naive patients: Start at ≤25 mcg/hr. It is recommended to titrate first with low doses of short-acting opioids before starting fentanyl patches.
Patients receiving a strong opioid analgesic: The initial dose should be based on the previous 24-hr opioid requirements. When transferring to fentanyl patches, the previous opioid treatment should be phased out gradually.
If a patient needs doses >100 mcg/hr, more than one patch may be used. Consider alternative or additional therapy if doses >300 mcg/hr are required. Replace the patch every 72 hr and put the new patch on a different site, and avoid using the same area of skin for a few days.
Elderly: Dose reduction may be needed.
