Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A) : Epinephrine should not be added to ropivacaine, to increase its duration of action
Reason (R) : All the local anesthetics cause vasoconstriction upon local administration, except ropivacaine and levobupivacaine
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A).
• B. Both (A) and (R) are correct but (R) is NOT the correct explanation of (A).
• C. (A) is correct but (R) is not correct.
• D. (A) is not correct but (R) is correct.

Hint:

Remember the vasoactive properties of local anesthetics:
- Lidocaine, Bupivacaine: Vasodilators (often need epinephrine to prolong action).
- Ropivacaine, Cocaine: Intrinsic vasoconstrictors (do not need epinephrine).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Local anesthetics block nerve conduction by inhibiting voltage-gated sodium channels.
Epinephrine is commonly added to local anesthetic solutions to cause vasoconstriction, which slows systemic absorption and prolongs the anesthetic effect.
However, some modern local anesthetics have unique intrinsic vasoactive properties.

Step 2: Detailed Explanation:
Let us evaluate both statements:
- Assertion (A): Ropivacaine is an amide local anesthetic with a long duration of action.
At clinically relevant concentrations, ropivacaine has intrinsic vasoconstrictive properties that limit its own systemic absorption.
Adding epinephrine to ropivacaine does not significantly prolong its block or decrease peak plasma concentrations.
Therefore, adding epinephrine is unnecessary and generally not recommended, making Assertion (A) correct.
- Reason (R): This statement is incorrect.
Almost all local anesthetics (e.g., lidocaine, bupivacaine, procaine) actually cause vasodilation at clinical concentrations, which increases systemic absorption.
The rare exceptions are cocaine, ropivacaine, and levobupivacaine, which cause vasoconstriction.
The statement in (R) incorrectly claims that most local anesthetics cause vasoconstriction. Thus, Reason (R) is false.

Step 3: Final Answer:
Assertion (A) is correct but Reason (R) is not correct.