A child developed methemoglobinemia after receiving local anaesthesia during a surgical procedure which was treated by the intravenous administration of methylene blue. Which of the following anaesthetic must have given in this child?
Procaine
Bupivacaine
Prilocaine
Lignocaine
Prilocaine is an intermediate-acting amino amide. Prilocaine has the highest clearance of the amino-amide anesthetics, impaing reduced risk of systemic toxicity. It has propensity to induce methemoglobinemia, which results from accumulation of one its metabolites, oho-toluidine, an oxidizing agent. Development of methemoglobinemia is dependent on the total dose administered, usually appearing after a dose of 8 mg/kg. If necessary, it can be treated by the intravenous administration of methylene blue (1-2 mg/kg). Ref: Drasner K. (2012). Chapter 26. Local Anesthetics. In B.G. Katzung, S.B. Masters, A.J. Trevor (Eds), Basic & Clinical Pharmacology, 12e.