Plasma concentrations of voriconazole in falcons

Abstract

Doses of 12.5 mg voriconazole/kg bodyweight administered every 12 hours by crop gavage to six falcons for 14 days provided peak plasma concentrations of more than 1 microg/ml, but the trough concentrations were lower and sometimes undetectable. Administering the same doses incorporated into meat that was fed to one falcon for seven days and to three falcons for up to 91 days provided similar plasma concentrations.

Aspergillusinfections in birds: a review

“…Dose not mentioned Voriconazole Oral 10 mg/kg q12 h (pigeon) (Beernaert et al, 2009a,b), q24 h (chickens) (Burhenne et al, 2008) (African grey parrots) (Scope et al, 2007) 12 to 18 mg/kg q12 h (African grey parrots) (Flammer & Orosz, 2008) 12.5 mg/kg q12 h, 3 days loading dose, then q24 h (raptors) Schmidt et al, 2007) 40 mg/kg q24 h (quails) (Tell et al, 2009) 5-fluorocytosine Oral 50 to 100 mg/kg q12 h (Flammer, 1993) 60 to 250 mg/kg q12 h (cage birds); 40 mg/kg q6 to 8 h (raptors) (Jenkins, 1991) 150 to 250 mg/kg q12 h 21 days (Bauck et al, 1992) 120 mg/kg q12 h 3 weeks (Westerhof, 1995) 75 to 120 mg/kg q24 h (dose/4 q6 h) (Redig & Duke, 1985) 120 mg/kg q6 h (Joseph et al, 1994) a Every.…”

Voriconazole

“…27,29 Nonetheless, the efficacy of VCZ with natural and/or experimental aspergillosis has been reported in falcons, a red-tailed hawk, Japanese quail, and domestic pigeons with effective treatment achieved at an every 12 hour interval. 28,31,32,35,36 Burhenne et al showed in their long-term study in chickens that tissue distribution of VCZ was adequate, so the authors concluded that the oral dosage of 10 mg/kg likely produces effective concentrations against A. fumigatus in most peripheral compartments and tissues, even 12 hours after administration. 30 This effect was not seen in the lung tissue of pigeons that were tested 12 hours after administration.…”

“…25,26 The pharamacokinetics of vorioconazole have been evaluated in Mallard ducks Amazon parrots (Amazona ventralis). 27,28,29,30,31,32,33,34 Oral bioavailability has been established in Mallard ducks, chickens, and pigeons at 61, 16, and 44%, respectively 27,30,32 ; it is unclear why this level is so much lower than humans (>90%).…”

“…32 This is likely an auto-induction effect; similarly, trough levels were in multiple-dose studies were consistently below plasma levels seen at 12 hours after a single dose in mallard ducks, red-tailed hawks, pigeons, African grey parrots, and Hispaniolan parrots, but not falcons, which had little change to trough concentrations on days 1 to 7 and a subsequent marked increased after the day 14 dose. 27,28,29,32,33,34 With trough levels falling below target plasma concentrations for VCZ, some studies recommended that dosing birds with VCZ may be most efficacious at a frequency of every 8 hours. 27,29 Nonetheless, the efficacy of VCZ with natural and/or experimental aspergillosis has been reported in falcons, a red-tailed hawk, Japanese quail, and domestic pigeons with effective treatment achieved at an every 12 hour interval.…”

“…1,27,28,29,30,31,32,33,34 In general, the elimination half-life was short in the studied avian species-1.45 to 1.99 hours in chickens (receiving oral doses of 5 to 15 mg/kg), 2.1 to 3.5 hours in red-tailed hawks (10 mg/kg), 1.1 to 1.6 hours in African grey parrots (6 to 18 mg/kg), 0.7 to 1.25 hours in Hispaniolan Amazon parrots (12 or 24 mg/kg)-except for pigeons, which had a half-life of 10.3 hours after receiving a dose of orally, twice a day). 32 This is likely an auto-induction effect; similarly, trough levels were in multiple-dose studies were consistently below plasma levels seen at 12 hours after a single dose in mallard ducks, red-tailed hawks, pigeons, African grey parrots, and Hispaniolan parrots, but not falcons, which had little change to trough concentrations on days 1 to 7 and a subsequent marked increased after the day 14 dose.…”