(01) Local Anesthetics

Question 1

1. Local anesthetics inhibit the action of what?
2. Lidocaine is metabolized primarily where?
3. Procaine is metabolized primarily where?
4. Procaine has a shorter duration in the body due to what?

Answer 1

1. voltage gated sodium channels
2. liver
3. blood
4. hydrolysis in the plasma rather than liver

Question 2

1. larger amounts required to desensitize inflamed tissues - increasing the probablility of what?
2. generally, local anesthetics cross the axonal membrane from the extracellular area to the axolemma best when the extracellular fluid is what?
3. The basis for the high efficacy of lidocaine on arrhythmias, at doses that don’t produce numbness throughout the body, is that what?
4. 5. Sympathomimetrics are frequently injected with local anesthetics to cause vasoconstriction and decrease local blood flow - thus doing what?

Answer 2

1. systemic toxicity
2. relatively basic environment with respect to the pKa of the drug
3. nerves that are frequently depolarized allow drug to enter channels and bind to its site of action more readily
4. preventing the washout of local anesthetics.