Barbiturates Flashcards
From what chemical compound are barbiturates derived?
Barbituric acid
Why is barbituric acid not used as an anesthetic?
It lacks hypnotic properties
Substitutions at which positions in the barbituric acid molecule make barbiturates thio or oxy barbiturates.
Position 2
Substituting a _________ atom at position 2 on a barbituric acid molecule creates a thiobarbiturate
Sulfur
Substituting a _____ atom at position 2 in the barbituric acid molecule creates an oxybarbiturate.
Oxygen
Is sodium pentothal an oxybarbiturate or thiobarbiturate?
Thiobarbiturate
Is methohexital an oxybarbiturate or a thiobarbiturate?
Oxybarbiturate
The type and position of substitutions on the barbituric acid molecule affects what properties of the drug?
The pH of thiopental and methohexital is alkaline, neutral or acidic
Alkaline
The pH of thiopental and methohexital is_____.
higher than 10
What are the advantages of the high pH of barbiturates?
It prevents bacterial growth and
Increases shelf life
What is the disadvantage of the high pH of barbiturates?
It will precipitate when mixed with acidic drugs such as neuromuscular blockers
What is the hazard of preciptation in an IV line?
It can irreversibly block intravenous delivery lines
Can form emboli
Are thiopental and methohexital R isomers, D isomers or a racemic mixture of isomers?
Racemic mixture their potencies are the summation of the potencies of the individual isomers
How are thiopental and methohexital metabolized?
