Temporary course of fluoxetine and norfluoxetine in German Shepherd and Akita Inu dogs

Abstract

The pharmacokinetics of fluoxetine were evaluated in two phylogenetically distant dog breeds. The quantification method was fine-tuned and validated through the mean, standard deviation and coefficient of variation (CV) for each sampling point. The CV values were around 2%. The detection limit was 3.36 ng/ml and corresponded to three times the signal noise of the blank sample. The limit of quantification (LOQ) was 10.53 ng/ml. The chromatographic analysis indicated that the maximum concentrations of fluoxetine were reached at two hours post-administration (Akika Inu: 41.8 ± 0.6 ng/ml; German Shepherd: 45.3 ± 1.4.0 ng/ml), while the minimum concentrations were reached at 80 hours (Akika Inu: 3.9 ± 0.1 ng/ml; German Shepherd: 3.9 ± 0.1 ng/ml). A significant difference between breeds was only found in the values reached at 2 h post-administration (p<0.05). Results may indicate that due to the differences in the time curve, drug management might be different between phylogenetically different breeds.