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