Monday Lecture: Local Anesthetics

Question 1

Low ___________ speeds the onset of action of local anesthetics.

Answer 1

pKa

Question 2

How does tissue acidosis affect local anesthetic efficacy?

Answer 2

It decreases the effectiveness. When the tissue pH lowers, it causes more of the local anesthetic to be ionized and not cross the membrane.

Question 3

Why does epinephrine slow the onset of action of lidocaine?

Answer 3

Epinephrine has to be mixed into an acidic solution. The acidic solution lowers the neutral form.

Question 4

Which area tends to have the higher serum level of anesthetic, femoral or intercostal?

Answer 4

Intercostal

This is the descending order of absorption in non-intravesicular sites: 
•Tracheal
•Epidural
• Brachial
• Femoral

Question 5

Which two drugs are the most common anesthetics for epidural infusion?

Answer 5

Ropivacaine and bupivacaine

Both of these drugs last a long time so require lower dosing.

Question 6

People typically report ______________ with IV lidocaine.

Answer 6

circumoral paresthesia, tinnitus, and a mettalic taste