The Effect of Some Local Anesthetics On Methemoglobin Levels and Erythrocyte Enzymes

Authors: Canan BAYAR, Nilgün SÜMER

Abstract: he aim of this study was to investigate the effects of articaine, bupivacaine and benzocaine on methemoglobin formation and to define the probable mechanism of methemoglobinemia caused by these local anesthetics. The effects of benzocaine, articaine and bupivacaine on (i) methemoglobin and ADP levels in erythrocytes, and on (ii) spontaneous formation of methemoglobin from oxyhemoglobin, as well as on NADH-methemoglobin reductase and glucose-6-phosphate dehydrogenase activities in hemolysates, were investigated. In erythrocytes, benzocaine increased methemoglobin levels from 1.40±0.07 % to 2.66±0.69 % in 5 hours, but articaine and bupivacaine had no effect. None of these local anesthetics had any effect on the other parameters investigated. Based on these findings, it was concluded that benzocaine-induced methemoglobin formation could be due to a metabolite that may be formed by incubation of the drug in erythrocyte suspension.

Keywords: Methemoglobin, Methemoglobinemia, Local Anesthetics, Benzocaine, Articaine, Bupivacaine