Which is the only topical amide anesthetic for use in the US?

Which is the only topical amide anesthetic for use in the US?

• A. Benzocaine
• B. Lidocaine
• C. Dyclonine HCl
• D. Tetracaine HCl

Answer: (B)

Topical local anesthetics are divided into two chemical families: esters and amides. This distinction matters because it influences how they are metabolized, how long their effect lasts, and their allergy profiles. Amide anesthetics are mainly broken down in the liver and tend to have a longer duration and a lower rate of allergic reactions compared with esters, which are rapidly hydrolyzed by plasma esterases and can more commonly trigger ester-type sensitivities. Among common topical options used in the United States, lidocaine is the only one that is an amide. Benzocaine and tetracaine are esters, so they fall outside the amide category. Dyclonine HCl is not an amide either, so it isn’t classified with lidocaine in the amide group. That’s why lidocaine is the best answer for the only topical amide anesthetic approved for use in the US.

Topical local anesthetics are divided into two chemical families: esters and amides. This distinction matters because it influences how they are metabolized, how long their effect lasts, and their allergy profiles. Amide anesthetics are mainly broken down in the liver and tend to have a longer duration and a lower rate of allergic reactions compared with esters, which are rapidly hydrolyzed by plasma esterases and can more commonly trigger ester-type sensitivities.

Among common topical options used in the United States, lidocaine is the only one that is an amide. Benzocaine and tetracaine are esters, so they fall outside the amide category. Dyclonine HCl is not an amide either, so it isn’t classified with lidocaine in the amide group. That’s why lidocaine is the best answer for the only topical amide anesthetic approved for use in the US.