Pharmacology · single question
What is the mechanism of action of local anesthetics?
Show answer and explanation
Correct answer: A. Sodium channel blocker (inhibits Na⁺ influx)
✓ A) Sodium channel blocker is correct.
Local anesthetics (lidocaine, articaine, mepivacaine, etc.) work by BLOCKING voltage-gated sodium channels. They enter the nerve cell (preferentially in the ionized form — uncharged base form penetrates the membrane, then re-ionizes inside to block the channel from within). This prevents Na⁺ influx during depolarization, stabilizes the membrane, and blocks propagation of the action potential. The result: loss of pain sensation without loss of consciousness. Smaller unmyelinated C fibers (pain) are blocked before larger myelinated A-beta fibers (touch/proprioception).
Local anesthetics (lidocaine, articaine, mepivacaine, etc.) work by BLOCKING voltage-gated sodium channels. They enter the nerve cell (preferentially in the ionized form — uncharged base form penetrates the membrane, then re-ionizes inside to block the channel from within). This prevents Na⁺ influx during depolarization, stabilizes the membrane, and blocks propagation of the action potential. The result: loss of pain sensation without loss of consciousness. Smaller unmyelinated C fibers (pain) are blocked before larger myelinated A-beta fibers (touch/proprioception).