Step 1: Two classes of local anesthetics.
Local anesthetics are broadly divided into two chemical classes based on the linkage connecting the aromatic head and the amino tail: ester-type (contain -COO- linkage) and amide-type (contain -NHCO- linkage).
Step 2: Identify amide-type agents.
Amide-type local anesthetics are metabolised by liver enzymes (cytochrome P450) and have a longer duration of action. Key examples: Lidocaine, Bupivacaine, Mepivacaine, Ropivacaine, Prilocaine. A helpful mnemonic: all amide-type agents have two letter "i" in their generic name (lIdocaIne, bupIvacaIne).
Step 3: Identify ester-type agents.
Procaine, Benzocaine, and Tetracaine are all ester-type local anesthetics. They are hydrolysed by plasma cholinesterases (pseudocholinesterase) and have a shorter duration.
Step 4: Apply to this question.
Among the options: Procaine = ester, Benzocaine = ester, Tetracaine = ester, Lidocaine = amide. Only Lidocaine is an amide-type local anesthetic.
Step 5: Confirm.
Lidocaine is the prototype amide-type local anesthetic, widely used for infiltration, nerve blocks, and as an antiarrhythmic.
Answer: Option (2) — Lidocaine