Term
Why is propofol prepared in an emulsion vehicle?
What is the emulsion? |
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Definition
because it is has very low water solubility
The emulsion is soybean oil and egg lecithin (from egg yolk) |
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Term
| T/F. Most reaction are due to the egg lecithin from the egg yolk. |
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Definition
| FALSE. They are from the proteins in the tiny amount of egg white that gets into emulsion after egg is separated |
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Term
What is the preservative for Diprivan?
What is the preservative for generic propofol? |
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Definition
sodium edenate (EDTA)
Sodium metabisulfite (careful in patients with sulfite allergy or allergy to red wine) |
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Term
| This drug is a propofol prodrug which is cleaved to propofol after administration by endothelial alkaline phosphatases |
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Definition
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Term
| T/F. fospropofol causes even more pain on injection than propofol because it has a pH of 3.5 |
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Definition
| FALSE. It is water soluble and does not require a painful emulsion vehicle for administration like propofol does |
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Term
| How does lidocaine lessen the pain on injection of propofol? |
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Definition
| It is NOT d/t numbing of the vessel. It is thought to be d/t increasing the pH of the solution when mixed with propofol. |
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Term
| Pharmacokinetics of propofol |
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Definition
RAPID distribution into brain tissue and rapid redistribution into other fatty tissues.
Metabolism is via phase I P450 system and phase II glucuronide and sulfate conjugation in liver. There is also some extrahepatic component- high levels of lung cell uptake but released mainly unchanged
propofol is excreted in kidneys |
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Term
A) How does propofol affect the fetus in a pregnant woman?
B)Does liver or kidney disease affect elimination of propofol? |
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Definition
A) It easily crosses placenta, but is rapidly metabolized by the fetus
B)Not significantly |
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Term
| Why is the high protein binding properties of propofol a concern? |
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Definition
| it can "knock off" other highly protein bound drugs and cause an increase in their effect. e.g. warfarin |
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Term
| What is a potential complication of mixing lidocaine with propofol in a syringe? |
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Definition
| It can cause oil droplet formation-- pulm embolism |
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Term
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Definition
> Enhances GABA activity like barbs and benzos
> weak base that is 99% non-ionized at physiologic pH
> Large Vd- reaches peak brain concentration within one minute
> Rapid recovery d/t rapid redistribution to fatty tissue and partly d/t metabolism
> metabolized RAPIDLY via plasma esterase hydrolysis of side chain ester group and hepatic P450 system
> induction similar to thiopental
> duration 5-10 minutes
> Elim. 1/2 time: 2-5 hrs
> minimal CV effects- better choice than barbs or propofol for pts with cardiac instabilities
> Less ventilatory depression than with barbs or propofol
> high incidence of myoclonus on rapid IV induction
> depresses cortisol synthesis in adrenal glands (not recommended for long term use) |
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Term
A) is ketamine lipid soluble?
B) does ketamine bind to protein well? |
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Definition
A) very lipid soluble
B) minimal protein binding |
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Term
| _________ are the only receptors that are voltage and ligand gated |
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Definition
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Term
| How is ketamine metabolized? |
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Definition
> N-demethylated (P450) to norketamine, which has appx 25% of ketamine's activity
> further metabolized by hydroxylation (P450) to hydroxynorketamine, which is inactive
> then it is glucuronated and excreted in urin |
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Term
| Mechanism of action of dexmedetomidine |
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Definition
binds to alpha-2 "auto-receptors" on pre-synaptic membrane that tell the neuron to stop releasing its neurotransmitter.
Remember the body's normal mechanism of stopping neurotransmitter release is that when the POST-synaptic membrane alpha-1 receptors get saturated with NT the NT will start binding to pre-synaptic alpha-2 receptors and now the body knows that it has enough NT and will stop releasing more. |
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