Effect of age on the pharmacokinetics of a single daily dose of gentamicin sulfate in healthy foals.
Abstract: Therapeutic drug monitoring in a small number of foals of various ages indicates that the standard adult dose of 6.6 mg/kg bwt q. 24 h for gentamicin is too low and a dose of 12 mg/kg bwt has been proposed. The pharmacokinetics of this dosage in foals and the ages at which this higher dose should be used have not previously been investigated. Objective: To determine the effect of age on the pharmacokinetics of a single 12 mg/kg bwt i.v. dose of gentamicin in foals. Methods: Six healthy foals were given a single i.v. dose of gentamicin at 1-3 days, 2, 4, 8 and 12 weeks of age. Plasma concentrations were measured using LC-MS/MS. Results: Elimination half-life (mean ± s.d.) was significantly longer in 1-3-day-old foals (8.2 ± 2.0 h) than in foals 4 weeks of age (3.7 ± 1.5 h) or older. Volume of distribution was significantly higher in 1-3-day-old foals (0.75 ± 0.20 l/kg bwt) than in 8- (0.27 ± 0.10 l/kg bwt) or 12-week-old foals (0.29 ± 0.11 l/kg bwt). Concentrations of gentamicin 1 h after administration were significantly lower in 1-3-day-old foals (20.52 ± 2.07 μg/ml) than in all other age groups (>42.16 ± 17.57 μg/ml). Concentrations of gentamicin 24 h after administration were significantly higher in the 1-3-day-old foals (1.97 ± 0.90 μg/ml) than in all the other age groups (<0.85 ± 0.46 μg/ml). Conclusions: The pharmacokinetics of gentamicin change considerably in the first 2 weeks of life. Conclusions: Intravenous administration of gentamicin at a dose of 12 mg/kg bwt q. 36 h would be required in foals less than 2 weeks of age. In foals 2 weeks of age or older, a lower dose of 6.6 mg/kg bwt given q. 24 h was predicted to be adequate.
© 2012 EVJ Ltd.
Publication Date: 2012-11-23 PubMed ID: 23173817DOI: 10.1111/j.2042-3306.2012.00683.xGoogle Scholar: Lookup
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- Clinical Trial
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research article investigates the effect of age on how newborn horses (foals) metabolize the antibiotic gentamicin, finding that younger foals require a higher dosage than usually given to adult horses, and outlining adjusted dosage recommendations based on age.
Objective of the Study
- The research aimed to establish how the age of foals affects the pharmacokinetics (drug absorption, distribution, metabolism, and excretion in the body) of gentamicin at a proposed higher dose of 12 mg/kg body weight (bwt). This is in contrast to the standard adult horse dose of 6.6 mg/kg bwt, which was suggested to be too low for foals.
Methodology
- Six healthy foals were administered a single intravenous (i.v.) dose of gentamicin at different ages: 1-3 days, 2, 4, 8, and 12 weeks.
- The concentration of gentamicin in their plasma was measured using a technique called LC-MS/MS (Liquid Chromatography-Mass Spectrometry).
Results
- The study found that the elimination half-life of gentamicin (the time taken for the concentration of the drug to reduce by half) was significantly longer in very young foals (1-3 days old) than in older foals, from 4 weeks onwards.
- The study also discovered that the volume of distribution (the theoretical volume that the drug would need to uniformly distribute to result in the observed blood concentration) was higher in very young foals compared to those aged 8 to 12 weeks.
- There was also a significant difference in the concentration of gentamicin detected 1 hour and 24 hours after administration, based on the age of the foal. Lower concentrations were found 1 hour after administering the drug in very young foals but were higher after 24 hours compared to all other age groups.
Conclusions
- The pharmacokinetics of gentamicin in foals change significantly within the first two weeks of life.
- For foals under two weeks old, a high dose of 12 mg/kg bwt every 36 hours was recommended. In contrast, for foals aged two weeks or older, a lower dose of 6.6 mg/kg bwt every 24 hours was deemed sufficient.
Cite This Article
APA
Burton AJ, Giguère S, Warner L, Alhamhoom Y, Arnold RD.
(2012).
Effect of age on the pharmacokinetics of a single daily dose of gentamicin sulfate in healthy foals.
Equine Vet J, 45(4), 507-511.
https://doi.org/10.1111/j.2042-3306.2012.00683.x Publication
Researcher Affiliations
- Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA.
MeSH Terms
- Aging
- Animals
- Animals, Newborn
- Anti-Bacterial Agents / blood
- Anti-Bacterial Agents / pharmacokinetics
- Area Under Curve
- Body Fluids / chemistry
- Chromatography, Liquid
- Drug Administration Schedule
- Female
- Gentamicins / blood
- Gentamicins / pharmacokinetics
- Half-Life
- Horses / blood
- Male
- Tandem Mass Spectrometry
Citations
This article has been cited 1 times.- Klein C, Caston S, Troy J. Hernia formation after single-stage umbilical vein marsupialization in three Percheron foals diagnosed with septic omphalophlebitis.. Clin Case Rep 2022 Aug;10(8):e6274.
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