A patient who is allergic to an ester would also be allergic to which of the following?

The correct answer is that a patient who is allergic to an ester would also be allergic to benzocaine. This is because benzocaine is an ester-type local anesthetic. Individuals who have an allergy to ester local anesthetics may experience adverse reactions due to the similar chemical structure and metabolic pathways of ester drugs.

Lidocaine and mepivacaine, on the other hand, are both amide-type anesthetics. Amides and esters are classified differently based on their chemical structure, and an allergy to an ester does not automatically imply an allergy to amides. Therefore, a patient allergic to an ester would not have a cross-reactive allergy with amide local anesthetics such as lidocaine and mepivacaine. Thus, benzocaine is the correct choice.