LEHNE PHARM LOCAL ANESTHETICS EXAM WITH
VERIFIED 100+ QUESTION AND ANSWERS AND NARRATED
RATIONALES |LATEST UPDATE 2026-2027 A+ TARGETED.
1. Local anesthetics primarily act by:
A) Blocking potassium channels
B) Blocking voltage-gated sodium channels
C) Activating calcium channels
D) Stimulating GABA receptors
Rationale: Local anesthetics prevent nerve impulse propagation by blocking
Na⁺ channels.
2. Which of the following is an ester local anesthetic?
A) Lidocaine
B) Procaine
C) Bupivacaine
D) Ropivacaine
Rationale: Procaine is metabolized by plasma cholinesterase (ester type).
3. Which local anesthetic is an amide?
A) Cocaine
B) Procaine
C) Lidocaine
D) Benzocaine
Rationale: Lidocaine is an amide-type drug metabolized in the liver.
4. The most common mechanism of metabolism for amide local anesthetics is:
A) Plasma cholinesterase hydrolysis
B) Hepatic metabolism
C) Renal excretion unchanged
D) Pulmonary breakdown
Rationale: Amides are primarily metabolized in the liver.
,5. Ester local anesthetics are mainly metabolized by:
A) Liver microsomes
B) Plasma pseudocholinesterase
C) Kidney enzymes
D) Pancreatic enzymes
Rationale: Esters undergo rapid hydrolysis in plasma.
6. Which local anesthetic is most lipid soluble and potent?
A) Procaine
B) Lidocaine
C) Bupivacaine
D) Chloroprocaine
Rationale: Higher lipid solubility increases potency and duration.
7. The onset of action of local anesthetics depends mainly on:
A) Protein binding
B) pKa and ionization
C) Renal clearance
D) Hepatic blood flow
Rationale: Lower pKa → more unionized drug → faster onset.
8. Infection at the injection site decreases local anesthetic effect because:
A) It increases lipid solubility
B) Tissue pH becomes acidic reducing unionized drug
C) It increases protein binding
D) It increases metabolism
Rationale: Acidic pH traps drug in ionized form.
9. Which agent is commonly used for surface anesthesia in ENT procedures?
A) Bupivacaine
B) Cocaine
C) Ropivacaine
D) Mepivacaine
Rationale: Cocaine is used topically for mucosal anesthesia and
vasoconstriction.
, 10.Addition of epinephrine to local anesthetics:
A) Shortens duration
B) Prolongs duration and reduces absorption
C) Prevents metabolism completely
D) Increases systemic toxicity
Rationale: Vasoconstriction reduces systemic uptake.
11.Toxicity of local anesthetics mainly affects:
A) Liver only
B) Kidneys only
C) CNS and cardiovascular system
D) Skin
Rationale: High plasma levels cause CNS excitation then depression and
cardiac effects.
12.Early sign of local anesthetic systemic toxicity (LAST):
A) Coma
B) Cardiac arrest
C) Tinnitus and circumoral numbness
D) Renal failure
Rationale: CNS symptoms appear first.
13.The most cardiotoxic local anesthetic is:
A) Lidocaine
B) Procaine
C) Chloroprocaine
D) Bupivacaine
Rationale: Strong cardiac sodium channel binding prolongs arrhythmias.
14.Which drug is least likely to cause allergic reactions?
A) Procaine
B) Benzocaine
C) Amide local anesthetics (e.g., lidocaine)
D) Tetracaine
Rationale: True allergy is more common with esters (PABA metabolites).
VERIFIED 100+ QUESTION AND ANSWERS AND NARRATED
RATIONALES |LATEST UPDATE 2026-2027 A+ TARGETED.
1. Local anesthetics primarily act by:
A) Blocking potassium channels
B) Blocking voltage-gated sodium channels
C) Activating calcium channels
D) Stimulating GABA receptors
Rationale: Local anesthetics prevent nerve impulse propagation by blocking
Na⁺ channels.
2. Which of the following is an ester local anesthetic?
A) Lidocaine
B) Procaine
C) Bupivacaine
D) Ropivacaine
Rationale: Procaine is metabolized by plasma cholinesterase (ester type).
3. Which local anesthetic is an amide?
A) Cocaine
B) Procaine
C) Lidocaine
D) Benzocaine
Rationale: Lidocaine is an amide-type drug metabolized in the liver.
4. The most common mechanism of metabolism for amide local anesthetics is:
A) Plasma cholinesterase hydrolysis
B) Hepatic metabolism
C) Renal excretion unchanged
D) Pulmonary breakdown
Rationale: Amides are primarily metabolized in the liver.
,5. Ester local anesthetics are mainly metabolized by:
A) Liver microsomes
B) Plasma pseudocholinesterase
C) Kidney enzymes
D) Pancreatic enzymes
Rationale: Esters undergo rapid hydrolysis in plasma.
6. Which local anesthetic is most lipid soluble and potent?
A) Procaine
B) Lidocaine
C) Bupivacaine
D) Chloroprocaine
Rationale: Higher lipid solubility increases potency and duration.
7. The onset of action of local anesthetics depends mainly on:
A) Protein binding
B) pKa and ionization
C) Renal clearance
D) Hepatic blood flow
Rationale: Lower pKa → more unionized drug → faster onset.
8. Infection at the injection site decreases local anesthetic effect because:
A) It increases lipid solubility
B) Tissue pH becomes acidic reducing unionized drug
C) It increases protein binding
D) It increases metabolism
Rationale: Acidic pH traps drug in ionized form.
9. Which agent is commonly used for surface anesthesia in ENT procedures?
A) Bupivacaine
B) Cocaine
C) Ropivacaine
D) Mepivacaine
Rationale: Cocaine is used topically for mucosal anesthesia and
vasoconstriction.
, 10.Addition of epinephrine to local anesthetics:
A) Shortens duration
B) Prolongs duration and reduces absorption
C) Prevents metabolism completely
D) Increases systemic toxicity
Rationale: Vasoconstriction reduces systemic uptake.
11.Toxicity of local anesthetics mainly affects:
A) Liver only
B) Kidneys only
C) CNS and cardiovascular system
D) Skin
Rationale: High plasma levels cause CNS excitation then depression and
cardiac effects.
12.Early sign of local anesthetic systemic toxicity (LAST):
A) Coma
B) Cardiac arrest
C) Tinnitus and circumoral numbness
D) Renal failure
Rationale: CNS symptoms appear first.
13.The most cardiotoxic local anesthetic is:
A) Lidocaine
B) Procaine
C) Chloroprocaine
D) Bupivacaine
Rationale: Strong cardiac sodium channel binding prolongs arrhythmias.
14.Which drug is least likely to cause allergic reactions?
A) Procaine
B) Benzocaine
C) Amide local anesthetics (e.g., lidocaine)
D) Tetracaine
Rationale: True allergy is more common with esters (PABA metabolites).
