The following statements about bupivacaine are true, except:
Bupivacaine and its congeners - Bupivacaine a long acting local anesthetic is very common in clinical use due to its good capability of differential block. The major demerit is that it is most cardio toxic. It is racemic mixture. Prilocaine is the only local anesthetic that is metabolized to o -toluidine, which conves hemoglobin to methemoglobin producing methemoglobinemia. This is usually significant with doses of prilocaine as large as 600mg. Benzocaine used in topical local anesthetic sprays can also cause dangerous Methemoglobinemia. Treatment of medically impoant methemoglobinemia includes intravenous methylene blue (1-2 mg/kg of a 1% solution over 5 min). Methylene blue acts by reducing methemoglobin (Fe 3+ ) to hemoglobin (Fe 2+ ).
Must never be injected into vein
More cardiotoxic than lignocaine
0.25 % is effective for sensory block
Produces methemoglobinemia
Regional Anesthesia