Editorial Type:
Pharmacology

Pharmacokinetics of N-acetylcysteine after oral and intravenous administration to healthy cats

Jennifer L. Buur College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA 91766.

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 DVM, PhD
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Pedro P. V. P. Diniz College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA 91766.

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Kursten V. Roderick Angell Animal Medical Center, 350 S Huntington Ave, Boston, MA 02130.

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Butch KuKanich Department of Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506.

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John H. Tegzes College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA 91766.

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DOI:
https://doi.org/10.2460/ajvr.74.2.290
Volume/Issue:
Volume 74: Issue 2
Online Publication Date:
01 Feb 2013
Restricted access
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Abstract

Objective—To describe the pharmacokinetics of N-acetylcysteine (NAC) in healthy cats after oral and IV administration.

Animals—6 healthy cats.

Procedures—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 and Clinical Relevance—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.

Abstract

Objective—To describe the pharmacokinetics of N-acetylcysteine (NAC) in healthy cats after oral and IV administration.

Animals—6 healthy cats.

Procedures—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 and Clinical Relevance—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.

Contributor Notes

Supported in part by the Western University of Health Sciences Competitive Intramural Grant Program and the Morris Animal Foundation Veterinary Student Scholar Program.

Presented as a poster presentation at the Morris Animal Foundation–Small Companion Animal Symposium, Denver, June 2011.

The authors thank Drs. David Clark and Marc Togneri for technical assistance.

Address correspondence to Dr. Buur (jbuur@westernu.edu).
Cover American Journal of Veterinary Research
American Journal of Veterinary Research
Publication Date:
01 Feb 2013

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