pharmacology- IV anaesthetics Flashcards
what is the formulation in a vial of propofol?
The formulation most used is;
1% propofol; 200mg in a 20 ml vial.
10% soybean oil + 1.2% purified egg phospholipid added as emulsifiers.
2.25% of glycerol as a tonicity-adjusting agent,
and sodium hydroxide to change the pH.
In America there is aslo EDTA added for its bacteriostatic properties.
describe the metabolism and excretion of propofol
Metabolism;
Propofol is oxidized to 1,4-diisopropyl quinol in the liver.
Propofol and 1,4-diisopropyl quinol are conjugated with glucuronic acid to propofol-1-glucuronide, quinol-1-glucuronide, and quinol-4-glucuronide, which then may be excreted by the kidneys.
The metabolites are thought to be inactive.
excretion;
via kidneys as above. after a 2.5 hour anaesthetic with propofol patients excrete propofol and its metabolites for over 60 hours.
only 1% is excreted in the urine unchanged..
2% is excreted in feces.
clearance is >1/5L/min which is exceeding that of hepatic blood indicating that there is a degree of extra hepatic metabolism (mostly in the kidneys and lungs)- which has been shown to occur in anhepatic patients in liver transplants.
