Procaine belongs to which type of local anesthetic?

• A. Amide-type
• B. Ester-type
• C. Mixed-type
• D. Natural alkaloid

Answer: (B)

Local anesthetics are categorized by the chemical bond linking the aromatic ring to the amine part: ester linkage versus amide linkage. Procaine contains an ester bond, so it’s classified as an ester-type local anesthetic. Ester types are rapidly hydrolyzed by plasma esterases, which gives them a shorter duration of action and can make allergic reactions more likely due to PABA-related metabolites. Amide-type anesthetics (like lidocaine) have an amide bond and are mainly broken down by the liver, usually with a longer duration. The other categories listed aren’t standard classifications for local anesthetics. So, procaine is an ester-type local anesthetic.