Evidence-Based Advances in Avian Medicine

Pharmacokinetic Behaviour of Enrofloxacin after Single Intramuscular Dosage in American Black Vultures (Coragyps atratus)

The aim of the study was to investigate the intramuscular pharmacokinetics of enrofloxacin in black vultures (Coragyps atratus). The pharmacokinetics of a single intramuscular dose (10 mg/kg) of enrofloxacin was studied in six vultures. Plasma concentrations of enrofloxacin and its active metabolite, ciprofloxacin, were determined by high-performance liquid chromatography (HPLCuv). Pharmacokinetic parameters were estimated using non-compartmental and compartmental analysis. After intramuscular administration, enrofloxacin showed a rapid and complete absorption, reaching a Cmax value of 3.26 ± 0.23 μg/mL at 1.75 ± 0.53 h. A long terminal half-life of 19.58 h has been observed. Using previously published MIC values to perform a PK/PD analysis, cumulative fraction responses obtained after Monte Carlo simulation for AUC/MIC > 30, 50 and 125 were 72.93%, 72.34% and 30.86% for E. coli and 89.29%, 88.89% and 58.57% for Mycoplasma synoviae, respectively. Cumulative fraction responses obtained for Cmax/MIC index were 33.93% and 40.18% for E. coli and M. synoviae, respectively. The intramuscular administration of 10 mg/kg could be appropriate to treat infectious diseases caused by gram-positive bacteria with MIC value lower than 1 µg/mL; however, although enrofloxacin showed a slow elimination in black vultures, plasma concentrations were insufficient to reach the gram-negative stablished breakpoints.

Pharmacokinetics of single dose oral Terbinafine in common shelducks (Tadorna tadorna)

Fungal disease is a major cause of morbidity and mortality in avian species; thus, antifungals are the treatment of choice. Despite widely used in clinical practice, terbinafine pharmacokinetic studies are scarce in literature and only cover some avian families, with marked differences between them. This study evaluates the pharmacokinetic behaviour of terbinafine after a single oral administration of 60 mg/kg in 7 healthy adult common shelducks (Tadorna tadorna) by measuring plasma concentrations through high-performance liquid chromatography (HPLC) at times 0, 30 min, 1, 2, 4, 6, 8, 10, 12, 24, 36 and 48 hr postadministration. Noncompartmental analyses of the data showed a C_max (geometric mean) of 5.43 µg/ml, t_max (median) 1.0 hr and AUC_0-∞ 29.70 mg h/L. Elimination half-life was 6.33 hr and MRT 6.61 hr. Plasma concentrations remained above previously described MIC for terbinafine in some fungal species for at least 6 to 8 hr. A single oral administration of 60 mg/kg terbinafine did not produce adverse effects and could be a good treatment choice for fungal diseases in anatids.

Clinical Management of Avian Renal Disease

Treatment of avian renal disease relies on supportive care, such as fluid therapy and nutritional support. Analgesia and adaptations of the environment are indicated in cases of renal disease associated with painful joints. Other treatments vary with the underlying etiology and may include systemic antibiotics, antifungal therapy, vitamin A supplementation, or chelation therapy.

Pharmacokinetics of intravenous and intramuscular danofloxacin in red-eared slider turtles (Trachemys scripta elegans)

This study aimed to investigate the pharmacokinetics of danofloxacin in red-eared slider turtle (Trachemys scripta elegans) following a single intravenous (IV) and intramuscular (IM) administrations of 6 mg/kg, using a two-way crossover study with 30-day washout period. Eight clinically healthy red-eared slider turtle weighing 410-600 g (mean 490 g) were used for the study. Danofloxacin concentrations were measured using the reversed-phase high-performance liquid chromatography. The plasma concentration-time data were evaluated by a non-compartmental method. After IV administration, the elimination half-life (t_1/2ʎz), mean residence time (MRT_0-∞), area under the concentration-time curve (AUC_0-∞), volume of distribution at steady state and total body clearance in plasma were 24.17 hr, 30.64 hr, 143.31 hr·µg/ml, 1.29 l/kg and 0.04 l/hr/kg, respectively. Following IM administration, t_1/2ʎz, MRT_0-∞, AUC_0-∞, peak concentration (C_max), time to reach C_max, and bioavailability in plasma were 32.00 hr, 41.15 hr, 198.23 hr·µg/ml, 8.75 µg/ml, 1.5 hr and 139.89%, respectively. Danofloxacin has clinically superior pharmacokinetic properties, including the complete IM absorption, slow elimination and wide volume of distribution in red-eared slider turtles. However, further pharmacokinetics/pharmacodynamics studies are necessary for the treatment of diseases caused by susceptible bacteria with known minimum inhibitory concentration values in red-eared slider turtles.