This local anesthetic is commonly used and has an onset of 2-5 minutes and lasts for 2-3 hours.

This local anesthetic is commonly used and has an onset of 2-5 minutes and lasts for 2-3 hours.

• A. Bupivacaine
• B. Lidocaine
• C. Prilocaine
• D. Ropivacaine

Answer: (B)

Fast onset with a moderate duration is a hallmark of lidocaine among common local anesthetics. An onset in the 2–5 minute range means the drug quickly penetrates nerve membranes to block sodium channels, producing anesthesia promptly. The 2–3 hour duration fits lidocaine well, especially when used with a vasoconstrictor like epinephrine, which extends its effect into the couple-of-hours window without making the block excessively long. Bupivacaine and ropivacaine tend to have slower onset but longer durations, often lasting well beyond a few hours. Prilocaine can also act quickly, but its typical duration is shorter than the 2–3 hours described unless supplemented, and its profile doesn’t align as cleanly with both the quick start and the specific time window given. So the combination of rapid onset and about a couple of hours of anesthesia best matches lidocaine.

Fast onset with a moderate duration is a hallmark of lidocaine among common local anesthetics. An onset in the 2–5 minute range means the drug quickly penetrates nerve membranes to block sodium channels, producing anesthesia promptly. The 2–3 hour duration fits lidocaine well, especially when used with a vasoconstrictor like epinephrine, which extends its effect into the couple-of-hours window without making the block excessively long.

Bupivacaine and ropivacaine tend to have slower onset but longer durations, often lasting well beyond a few hours. Prilocaine can also act quickly, but its typical duration is shorter than the 2–3 hours described unless supplemented, and its profile doesn’t align as cleanly with both the quick start and the specific time window given.

So the combination of rapid onset and about a couple of hours of anesthesia best matches lidocaine.