Which of the following local anesthetics is an ester?

Tetracaine is recognized as an ester-type local anesthetic due to its chemical structure, which includes an ester bond in its molecular configuration. Esters are characterized by the presence of a carbonyl group adjacent to an ether linkage, specifically the -COO- group, which is prominent in tetracaine.

In contrast, lidocaine, bupivacaine, and ropivacaine are classified as amide local anesthetics. Amides contain a carbonyl group bonded to a nitrogen atom, differentiating them from esters. The distinction between ester and amide local anesthetics is significant in clinical practice, affecting the metabolism and potential hypersensitivity reactions. Esters, like tetracaine, are typically metabolized by plasma esterases, whereas amides are primarily metabolized in the liver.

Understanding the classification helps clinicians make informed choices regarding local anesthetic use, especially concerning patient allergies and the duration of anesthesia based on superficial or deep tissue penetration. Thus, tetracaine serves as an exemplar of the ester group among local anesthetics.