Propofol Flashcards
Is propofol a weak acid or weak base, and what is it’s pKa?
Weak acid with pKa of 11. Single hydroxyl group, so high pKa. Almost completely unionised at pH 7.4. Will readily cross lipid membranes such as the blood-brain barrier to be able to diffuse to the effect site.
What is the volume of distribution of propofol?
4.0 L/kg. Largest of the induction agents due to lipid solubility
What is the clearance rate of propofol?
30-60 ml/kg/min. Relatively rapid, useful in infusion
What is the elimination half-life of propofol?
5-12 h. Longer when given via infusion (see the page on context-sensitive half-time later in this session)
How much propofol is protein bound?
98%
What is the context sensitive half time for a propofol infusion lasting 8 hours?
20 mins
Regarding the presentation and structure of propofol (true or false):
Propofol is a phencyclidine derivative
False. Propofol is a phenolic derivative.
Regarding the presentation and structure of propofol (true or false):
Propofol is presented as a 1% or 2% lipid emulsion
True
Regarding the presentation and structure of propofol (true or false):
Propofol is light-sensitive
False. Propofol is not light-sensitive and can be stored in clear glass vials.
Regarding the presentation and structure of propofol (true or false):
Propofol is stable at room temperature
True
Regarding the presentation and structure of propofol (true or false):
Propofol is a weak base
False. Propofol is a weak acid.
Regarding the presentation and structure of propofol (true or false):
Propofol has a pKa of 11
True
Regarding the pharmacokinetics of propofol (true or false):
Propofol has a volume of distribution of 2.5 L/kg
False. Propofol has the largest volume of distribution of the induction agents at 4 L/kg
Regarding the pharmacokinetics of propofol (true or false):
Propofol is 90% protein bound
False. Propofol is 98% protein bound.
Regarding the pharmacokinetics of propofol (true or false):
Propofol has an elimination half-life of 5-12 hours
True
Regarding the pharmacokinetics of propofol (true or false):
Propofol is largely metabolised in the liver
True
Regarding the pharmacokinetics of propofol (true or false):
Emergence following propofol infusion is relatively slow
False. Due to relatively rapid clearance via both hepatic and renal metabolism.
Propofol (true or false):
Reduces systemic vascular resistance
True
Propofol (true or false):
Causes bronchoconstriction
False. Propofol causes bronchodilation.
Propofol (true or false):
Increases cerebral oxygen requirement
False. Propofol reduces cerebral oxygen requirement.
Propofol (true or false):
Is an antiemetic due to D2 receptor agonism
False. Propofol is a D2 receptor antagonist.
Propofol (true or false):
Is laryngeal reflex sparing
False. Propofol blunts the laryngeal reflex.
Regarding the clinical uses of propofol (true or false):
The standard adult induction dose is 3-4 mg/kg
False. The standard adult induction dose is 1- 2 mg/kg
Regarding the clinical uses of propofol (true or false):
Pain on injection can be mitigated by the addition of 1% lidocaine
True
Regarding the clinical uses of propofol (true or false):
It is contraindicated in patients with malignant hyperthermia
False. It is indicated in patients with malignant hyperthermia.
Regarding the clinical uses of propofol (true or false):
It can be used to reduce the risk of postoperative nausea and vomiting
True
Regarding the clinical uses of propofol (true or false):
The Bristol algorithm is an example of a target controlled infusion model
False. It is an example of a manual controlled infusion model.
Regarding the clinical uses of propofol (true or false):
Both the Schnider and Marsh models utilise lean body weight
False. Schnider uses actual body weight along with height, age and gender as part of its mathematical modelling.
Regarding the clinical uses of propofol (true or false):
With propofol infusion alone, most patients will go to sleep at an effect target of 2.5-3 μg/ml
True
What receptors does propofol act upon to cause sedation?
Beta subunit of GABA predominantly. However, it also also enhances the effects of glycine which is the major inhibitory transmitter in the brainstem and spinal cord. Furthermore, it inhibits neurotransmission at excitatory central nicotinic acetylcholine receptors.
Regarding propofol (true or false):
Glucuronidation occurs through the hydroxyl group at position 1
True.
