Local Anesthetics

Question 1

Local anesthetics

Answer 1

Esters (have only one “I” in their names)
-higher allergic tendency
Tetracaine, procaine, benzocaine

Amides (have 2 “I” in their names)
Bupivacaine, Ropivacaine, Lidocaine

Question 2

Half life of local anesthetics

Answer 2

Procaine = shortest half life (1-2 mins)
Ropivacaine = longest half life (4.2 hrs)

Question 3

Why should you not inject local anesthetics into an abscess during I&D?

Answer 3

It wont work due to the acidic environment of the abscess

below pKa = charge form will dominate w/c cant cross the barrier

Question 4

CNS effects of local anesthetics

Answer 4

Generalized tonic-clonic seizures

Question 5

Only local anesthetic that vasoconstricts

Answer 5

Cocaine

Question 6

Highest allergic potential among local anesthetics

Answer 6

Tetracaine

Question 7

Class Local Anesthetic

Uses: Anti-arrythmic (group 1B; used in post MI & digitalis toxicity)

Answer 7

Lidocaine

Question 8

Lidocaine toxic dose

Answer 8

5 mg/kg

Question 9

Class: Local anesthetic
Use: Dental anesthesia
SE: methemoglobinemia

Answer 9

Prilocaine

Antidote: Methylene blue
- convert ferric (Fe3+) to ferrous (Fe2+)

Question 10

Cardiotoxic local anesthetic

Answer 10

Bupivacaine

Treat w/ intralipid (fat emulsion used in TPN)