CRDTS Local Anesthesia Practice Test

Local anesthetic solutions that include a vasoconstrictor like epinephrine are prone to oxidative degradation; preserving the vasoconstrictor’s potency requires an antioxidant. Sodium bisulfite acts as a sulfur-containing antioxidant that scavenges oxidizing species and helps keep epinephrine in its active form, preventing loss of effectiveness. Sodium bicarbonate is just a buffer and doesn’t prevent oxidation. Ascorbic acid is an antioxidant in some contexts but isn’t the standard additive in these anesthetic formulations due to compatibility issues. Glutathione is a strong intracellular antioxidant but isn’t used as a preservative in local anesthetic solutions. Therefore, sodium bisulfite is the antioxidant that prevents oxidative/biochemical degradation of the local anesthetic solution.