Which of the following local anesthetics is least likely to cause an allergic reaction?

Lidocaine is considered the local anesthetic least likely to cause an allergic reaction primarily due to its chemical structure and the fact that it is an amide-type anesthetic. Amide anesthetics, such as lidocaine, have a lower incidence of allergic reactions compared to ester-type anesthetics like procaine. This is because allergic responses are often related to the breakdown products of esters, which can trigger immune responses in some individuals.

Additionally, lidocaine is widely used and has a well-established safety profile, lending further support to its lower likelihood of eliciting allergic reactions. The risk of allergy is generally associated with the preservatives or additives found in certain formulations rather than the anesthetic agent itself, and most lidocaine preparations do not contain such additives.

In contrast, procaine, being an ester, can result in allergic reactions more frequently due to its metabolism to para-aminobenzoic acid (PABA), a compound that can provoke immune responses. Articaine and bupivacaine, while also amides, have specific characteristics and usages that can make allergic reactions more of a concern in certain contexts, particularly in individuals with known sensitivities. Thus, lidocaine is favored for its reliability and lower risk profile regarding allergies in