Which anesthetic would produce the longest duration of action for a local anesthetic procedure?

• A. Articaine with epinephrine
• B. Mepivacaine with vasoconstrictor
• C. Prilocaine with felypressin
• D. Lidocaine 2% with epinephrine 1:50,000

Answer: (D)

The main idea is that how long a local anesthetic lasts is mainly controlled by how well the surrounding blood vessels are constricted. A strong vasoconstrictor reduces blood flow, so the drug stays in the tissue longer and continues to numb the nerve.

Among the options, using lidocaine with epinephrine at a high concentration provides the strongest and most sustained vasoconstriction. That means the anesthetic remains near the nerve longer, delaying its clearance from the injection site, which extends both pulpal and soft-tissue anesthesia more than the other combinations.

The other choices either involve a weaker vasoconstrictor or a vasoconstrictor with different dynamics, or use an anesthetic with diffusion characteristics that don’t translate to as long a duration in this comparison. So lidocaine with epinephrine 1:50,000 tends to give the longest duration.