Which local anesthetic is known for its potential to cause methemoglobinemia?

Prilocaine is known for its potential to cause methemoglobinemia, a condition where hemoglobin is modified to methemoglobin, which cannot effectively carry oxygen. This is primarily due to the metabolism of prilocaine into o-toluidine, a compound that can oxidize ferrous iron (Fe2+) in hemoglobin to ferric iron (Fe3+), leading to the production of methemoglobin.

Although other local anesthetics such as lidocaine, bupivacaine, and mepivacaine have their own specific side effects, they do not carry the same risk for methemoglobinemia. Lidocaine is commonly used without this concern, while bupivacaine and mepivacaine also do not have the same metabolite-related risk of producing methemoglobin. Therefore, prilocaine stands out for this particular side effect, making it essential for practitioners to be aware of its use in patients who may be at risk for methemoglobinemia, particularly in scenarios involving larger doses or in patients with certain hemoglobin disorders.