## Core Concept
Local anesthetics work by blocking the sodium channels in the neuronal membrane, thereby preventing the initiation and transmission of nerve impulses. This action is crucial for providing regional anesthesia or numbing a specific area of the body. The effectiveness and characteristics of local anesthetics depend on their chemical structure, which influences their potency, onset, and duration of action.

## Why the Correct Answer is Right
The correct statement regarding local anesthetics needs to be identified based on their pharmacological properties. However, since the specific details of the options (A, B, C, D) are not provided, a general principle is highlighted: Local anesthetics are weak bases and exist in two forms - the unionized form, which is lipid-soluble and can penetrate the neuronal membrane, and the ionized form, which interacts with the sodium channel. This dual nature affects their onset and duration of action.

## Why Each Wrong Option is Incorrect
- **Option A:** Without specific details, a common misconception could be that local anesthetics act by blocking potassium channels. However, their primary action is on sodium channels.
- **Option B:** Another potential misconception might be that local anesthetics are only effective on sensory nerves. While they are commonly used for sensory blockade, they can also block motor nerves, leading to muscle weakness or paralysis.
- **Option C:** If an option suggests that local anesthetics work by depolarizing the nerve membrane, this would be incorrect. Instead, they stabilize the membrane by blocking sodium influx, preventing depolarization.
- **Option D:** If an option states that ester-type local anesthetics are metabolized by plasma cholinesterases, this is actually correct and not the false statement we're looking for.

## Clinical Pearl / High-Yield Fact
A key point to remember is that the addition of a vasoconstrictor (like epinephrine) to a local anesthetic can prolong its duration of action and reduce systemic toxicity by limiting the spread of the anesthetic. However, this also risks causing local tissue ischemia.

## Correct Answer: D.