Which local anesthetic is both an amide and an ester?

Which local anesthetic is both an amide and an ester?

• A. Articaine (Septocaine)
• B. Lidocaine (Xylocaine)
• C. Prilocaine (Citanest)
• D. Mepivacaine (Carbocaine)

Answer: (A)

The key idea is that local anesthetics are categorized by their chemical linkage, amide or ester. Articaine is unique because its molecule contains an amide bond like the others, but it also has an ester linkage. That ester portion makes articaine susceptible to hydrolysis by plasma esterases in addition to hepatic metabolism, so it’s effectively processed by both pathways. This dual metabolism tends to improve clearance and can contribute to a favorable safety profile, while still providing strong anesthesia and good diffusion. The other common anesthetics shown are true amides with no ester bond, so they are metabolized primarily by the liver and don’t have the plasma ester hydrolysis pathway. Hence, articaine is the one that is both amide and ester.

The key idea is that local anesthetics are categorized by their chemical linkage, amide or ester. Articaine is unique because its molecule contains an amide bond like the others, but it also has an ester linkage. That ester portion makes articaine susceptible to hydrolysis by plasma esterases in addition to hepatic metabolism, so it’s effectively processed by both pathways. This dual metabolism tends to improve clearance and can contribute to a favorable safety profile, while still providing strong anesthesia and good diffusion. The other common anesthetics shown are true amides with no ester bond, so they are metabolized primarily by the liver and don’t have the plasma ester hydrolysis pathway. Hence, articaine is the one that is both amide and ester.