Fentanyl Flashcards
What class of opioid is fentanyl
Synthetic phenylpiperidine derivative
Outline the pharmaceutical aspects
Colourless solution for injection containing 50mcg/mL
Transdermal patches 25-100mcg/hr
Lozenges 200mcg-1.6mg
What is the morphine equivalence
Why is it more potent than Morphine
100x more potent
10mg Morphine = 100mcg Fentanyl
~600x more lipid soluble than Morphine
What are the uses of Fentanyl
Analgesia (1-2mcg/kg)
Induction dose for blunting laryngeal reflexes (50-100mcg)
Augment effects of local anaesthetics in spinal/epidural
What is the pKa
8.4
What percent is unionised at pH 7.4
8.5% (highly ionised)
What is the volume of distribution
4L/kg
What is the clearance
13mL/kg/min
Outline the metabolism
Hepatic metabolism
De-methylation to Norfentanyl (clinically inactive)
Hydroxylation of both fentanyl and norfentanyl
What is the elimination half time
190mins
Longer than Morphine - higher lipid solubility and larger Vd
What is the peak effect time
3-5mins
What are the benefits of Fentanyl over Morphine
Greater haemodynamic stability
No significant histamine release
Faster onset of action
No active metabolites
What percent is protein bound
85%
