Which type of anesthetic is typically contraindicated in patients with a known allergy to PABA?

Benzocaine is a topical anesthetic that is typically contraindicated in patients with a known allergy to PABA (para-aminobenzoic acid). Benzocaine is an ester-type local anesthetic, and its structure closely resembles PABA. Individuals who are allergic to PABA may also react to substances that are structurally similar, such as benzocaine. Therefore, using benzocaine in these patients can lead to allergic reactions, making it unsafe for them.

In contrast, lidocaine, mepivacaine, and articaine are amide-type local anesthetics, which are less commonly associated with PABA allergies. Amides do not have the same chemical structure as PABA and are generally considered safer options for patients with a PABA allergy. Thus, when treating patients with a known allergy to PABA, benzocaine should be avoided, while the amide anesthetics can be used with caution.