Which local anesthetic is LEAST likely to cause an allergic reaction?

Lidocaine is recognized as the local anesthetic least likely to cause an allergic reaction among the options provided. The primary reason for this is its chemical structure and the fact that lidocaine is an amide-type local anesthetic. Amides are generally associated with a lower incidence of allergic reactions compared to esters, as amide anesthetics do not contain the para-aminobenzoic acid (PABA) group that is often implicated in allergic responses associated with ester anesthetics such as procaine and tetracaine.

In addition, lidocaine has been used extensively in clinical practice, and while allergic reactions can occur with any medication, the prevalence of such reactions with lidocaine is significantly less than that seen with ester-type local anesthetics. This clinical experience further supports the understanding that lidocaine is safer regarding the risk of allergies.

Thus, the choice of lidocaine aligns with the pharmacological understanding of local anesthetic agents and their respective allergic potential.