Pharmacokinetics of N-acetylcysteine after oral and intravenous administration to healthy cats.
OBJECTIVE
To describe the pharmacokinetics of N-acetylcysteine (NAC) in healthy cats after oral and IV administration.


METHODS
6 healthy cats.


METHODS
In a crossover study, cats received NAC (100 mg/kg) via IV and oral routes of administration; there was a 4-week washout period between treatments. Plasma samples were obtained at 0, 5, 15, 30, and 45 minutes and 1, 2, 4, 8, 12, 24, 36, and 48 hours after administration, and NAC concentrations were quantified by use of a validated high-performance liquid chromatography-mass spectrometry protocol. Data were analyzed via compartmental and noncompartmental pharmacokinetic analysis.


RESULTS
Pharmacokinetics for both routes of administration were best described by a 2-compartment model. Mean ± SD elimination half-life was 0.78 ± 0.16 hours and 1.34 ± 0.24 hours for the IV and oral routes of administration, respectively. Mean bioavailability of NAC after oral administration was 19.3 ± 4.4%.


CONCLUSIONS
The pharmacokinetics of NAC for this small population of healthy cats differed from values reported for humans. Assuming there would be similar pharmacokinetics in diseased cats, dose extrapolations from human medicine may result in underdosing of NAC in cats with acute disease. Despite the low bioavailability, plasma concentrations of NAC after oral administration at 100 mg/kg may be effective in the treatment of chronic diseases.
College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA 91766, USA. jbuur@westernu.edu
Jennifer L
JL
Buur
Pedro P V P
PP
Diniz
Kursten V
KV
Roderick
Butch
B
KuKanich
John H
JH
Tegzes
D000111:Acetylcysteine / Q000008:administration & dosage / Q000493:pharmacokinetics*; D061605:Administration, Intravenous / Q000662:veterinary; D000284:Administration, Oral; D000818:Animals; D000998:Antiviral Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D019540:Area Under Curve; D001682:Biological Availability; D002415:Cats / Q000502:physiology*; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D018592:Cross-Over Studies; D005260:Female; D016166:Free Radical Scavengers / Q000008:administration & dosage / Q000493:pharmacokinetics*; D006207:Half-Life; D008297:Male; D013058:Mass Spectrometry / Q000662:veterinary
D000998:Antiviral Agents; D016166:Free Radical Scavengers; D000111:Acetylcysteine