Local Anesthetics Flashcards
Which local anesthetics are esters and which are amides?
Esters: Procaine, Tetracaine, Cocaine
Amides: Lidocaine, Mepivacaine, Bupivacaine, Prilocaine, Dibucaine
Where are Amide local anesthetics metabolized?
Liver
Where are ester local anethetics metabolized?
By esterases in the plasma
Which local anesthetic has an ability to cause methemoglobinemia?
Prilocaine
What is the mechanism of action for local anesthetics?
They prevent the generation of nerve impulses by interfering with sodium transport into the neuron.
How are local anesthetics absorbed?
Only the non-ionized (or free base form) can penetrate tissue membranes.
How does inflamed tissue affect local anesthetic?
Inflamed tissue has a lower pH, which decreases the amount of non-ionized form available to penetrate.
The duration of lidocaine would be increased in the presence of which medication?
Propranolol - interacts with lidocaine in2 ways.
- Slowing down the heart via beta receptor blockade, blood delivery to liver is slowed
- Competes for same liver enzyme
What does an overdose of local anesthetics cause?
- Cardiovascular collapse due to myocardial depression
The duration of action of lidocaine would be increased in the presence of what medication?
Propanolol
