A weak acid becomes more than 50% un-ionized following IV injection (blood pH = 7.4). The pKa of this weak acid could be...
Answer
7.6
7.4
7.2
1.5
Question 2
Question
When injected into the body, any of the local anesthetics used currently in clinical practice will be:
Answer
less than 50% un-ionized
more than 50% un-ionized
50% un-ionized
100% un-ionized
Question 3
Question
Sodium drug has pKa of 8.2. When injected into the blood, this drug will become:
Answer
less than 50% un-ionized
more than 50% un-ionized
50% un-ionized
100% un-ionized
Question 4
Question
What situation most facilitates accumulation of local anesthetic by the fetus?
Answer
maternal acidosis and fetal acidosis
maternal acidosis and fetal alkalosis
maternal alkalosis and fetal alkalosis
maternal alkalosis and fetal acidosis
Question 5
Question
Potency is determined by what property(ies) of a local anesthetic?
Answer
pKa
lipid solubility
protein binding
both lipid solubility and protein binding
Question 6
Question
Speed of onset is determined by what property(ies) of a local anesthetic?
Answer
pKa
lipid solubility
protein binding
both lipid solubility and protein binding
Question 7
Question
Duration of action is determined by what property(ies) of a local anesthetic?
Answer
pKa
lipid solubility
protein binding
both lipid solubility and protein binding
Question 8
Question
Local anesthetics work on which segment(s) of the neuron?
Answer
axon only
cell body and axon
axon and nerve terminal
cell body, axon and nerve terminal
Question 9
Question
Conduction block occurs when the...
Answer
ionized form of the local anesthetic binds to the voltage-gated sodium channel outside the cell
ionized form of the local anesthetic binds to the voltage-gated sodium channel inside the cell
un-ionized form of the local anesthetic binds to the voltage-gated sodium channel outside the cell
un-ionized form of the local anesthetic binds to the voltage-gated sodium channel inside the cell
Question 10
Question
You can make your own local anesthetic. If you want the local anesthetic to have a fast onset, you will want to have the local anesthetic have what pKa?
Answer
2.3
7.0
7.4
11.5
Question 11
Question
Injection of local anesthetic at which of the following sites is most likely to result in systemic toxicity?
Answer
epidural space
paracervical tissue
intercostal muscles
brachial plexus
Question 12
Question
Methemoglobinemia can occur if what local anesthetic is used?
Answer
Tetracaine
Prilocaine
Ropivacaine
Mepivacaine
Question 13
Question
What condition most prevents passage of local anesthetic from fetus to mom?