Which combination of local anesthetics is classified under esters?

The combination of local anesthetics classified under esters is indeed that of Tetracaine and Benzocaine. Esters and amides are the two main categories of local anesthetics, and they differ primarily in their chemical structure and metabolism in the body.

Esters, such as Tetracaine and Benzocaine, are characterized by their ester linkage in the chemical structure and are often associated with a higher incidence of allergic reactions compared to amides. Tetracaine is a potent local anesthetic used for spinal anesthesia and topical applications, while Benzocaine is commonly used in over-the-counter preparations for its topical analgesic properties.

In contrast, the other combinations listed contain amide anesthetics. Lidocaine and Mepivacaine, Articaine and Prilocaine, as well as Septocaine and Bupivacaine all belong to the amide class. These anesthetics are typically less allergenic and are metabolized in the liver, which distinguishes them from esters that are usually hydrolyzed by plasma esterases. Understanding these classifications is key in the use of local anesthetics, particularly regarding patient safety and efficacy in clinical practice.