USGS Home
Contact USGS
Search USGS

UMESC Publications

Pharmacokinetics of benzocaine in rainbow trout (Oncorhynchus mykiss) after intraarterial dosing

Meinertz, J. R., Stehly, G. R., and Gingerich, W. H., 1996, Pharmacokinetics of benzocaine in rainbow trout (Oncorhynchus mykiss) after intraarterial dosing: Aquaculture, v. 148, no. 1, p. 39-48.

Abstract

The pharmacokinetics of benzocaine were analyzed in rainbow trout (Oncorhynchus mykiss) after intraarterial bolus administration of benzocaine at nominal concentrations of 6 and 9 mg/kg. Distributive phase pharmacokinetic parameters were difficult to estimate. Benzocaine concentrations at 2 min after dosing were highly variable and decreased rapidly within the first 10 min. Benzocaine concentrations were near or below the quantitation limit 90 min after dosing. A three-compartment pharmacokinetic model best described benzocaine concentrations in plasma. The apparent volume of distribution at steady state and total body clearance increased with respect to dose. Since the mean residence time was similar at both dosages, the differences in the apparent volume of distribution at steady state and total body clearance may have been the result of data variability or the degree of anaesthesia rather than dose dependency. The model parameters indicated that distribution of benzocaine outside of the plasma was limited. Despite the initial rapid distribution and elimination of benzocaine from plasma, terminal phase benzocaine elimination was relatively slow (terminal elimination phase half-lives of 89 and 109 min).

Keywords: benzocaine, anaesthesia, pharmacokinetics, Oncorhynchus mykiss