- Allergic reactions are extremely rare to local anesthetics but may occur with the "Amides". - If they occur, it is more likely due to a preservative found in some multi-dose vials: methylparaben. - Either switch to a single dose vial without preservative or change to an "Ester" where there is no cross-reactivity Amides: Bupivacaine, Etidocaine, Lidocaine, Mepivacaine, Prilocaine, Ropivacaine Esters: Chloroprocaine, cocaine, procaine, tetracaine
