LIDOCAINE ELIMINATION AND MONOETHYLGLYCINEXYLIDIDE FORMATION IN THE DEHYDRATED CAMEL

The elimination kinetics and the formation of the monoethylglycinexyli dide (MEGX), a major metabolite of lidocaine, were studied in camels d eprived of water for 14 days. The study was conducted on four camels i n a crossover design. Lidocaine was administered intravenously at a do se of 1 mg/kg to adult female camels when water was given ad libitum ( stage 1) and to the same camels after 14 days of dehydration. Blood sa mples were taken up to 6 h after dosing. Serum lidocaine and MEGX leve ls were analysed by polarization fluorescence immunoassay, The elimina tion profiles of lidocaine and the formation of the metabolite MEGX in the two phases of the study were essentially identical, No difference in any pharmacokinetic parameter was noticed between normally hydrate d and water-deprived camels. It is thus concluded that dehydration doe s not affect the cytochrome P450 isozymes involved in degradation of l idocaine to MEGX nor does it affect the hepatic blood flow, which is a major determinant in the clearance of lidocaine. The very low clearan ce of lidocaine in the camel in comparison with other ruminant or mono gastric mammals may be associated with the camel's ability to survive drought in the desert.