Pharmacokinetics and effects of aminorex in horses.
Abstract: To investigate the pharmacokinetics and behavioral effects of aminorex administered IV and PO in horses. Methods: 7 Thoroughbreds. Methods: In a cross-over design, aminorex (0.03 mg/kg) was administered IV or PO. Plasma and urinary aminorex concentrations were determined via liquid chromatography- mass spectrometry. Results: Decrease of aminorex from plasma following IV administration was described by a 3-compartment pharmacokinetic model. Median (range) values of alpha, beta, and gamma half-lives were 0.04 (0.01 to 0.28), 2.30 (1.23 to 3.09), and 18.82 (8.13 to 46.64) hours, respectively. Total body and renal clearance, the area under the plasma time curve, and initial volume of distribution were 37.26 (28.61 to 56.24) mL x min/kg, 1.25 (0.85 to 2.05) mL x min/kg, 13.39 (8.82 to 17.37) ng x h/mL, and 1.44 (0.10 to 3.64) L/kg, respectively. Oral administration was described by a 2-compartment model with first-order absorption, elimination from the central compartment, and distribution into peripheral compartments. The absorption half-life was 0.29 (0.12 to 1.07) hours, whereas the beta and gamma elimination phases were 1.93 (1.01 to 3.17) and 23.57 (15.16 to 47.45) hours, respectively. The area under the curve for PO administration was 10.38 (4.85 to 13.40) ng.h/mL and the fractional absorption was 81.8% (33.8% to 86.9%). Conclusions: Aminorex administered IV had a large volume of distribution, initial rapid decrease, and an extended terminal elimination. Following PO administration, there was rapid absorption, rapid initial decrease, and an extended terminal elimination. At a dose of 0.03 mg/kg, the only effects detected were transient and central in origin and were observed only following IV administration.
Publication Date: 2008-05-02 PubMed ID: 18447801DOI: 10.2460/ajvr.69.5.675Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research study investigates the pharmacokinetics, which is the movement of drugs within the body, and behavioral effects of aminorex, a stimulant drug, in horses. The drug was given intravenously (directly into a vein) or orally, and its concentration levels were observed in the horses’ plasma and urine.
Methodology
- The research was carried out using seven Thoroughbred horses.
- The stimulant drug, aminorex, was administered through two methods: intravenously (directly into the bloodstream) and orally (by mouth).
- The amount of aminorex given was 0.03 mg/kg, carefully calculated based on each horse’s weight.
- The concentrations of aminorex in plasma and urine of the horses were measured using liquid chromatography-mass spectrometry, a powerful analytical method used to identify the various substances in a complex sample.
Results and Findings
- The rate of decrease of aminorex from the plasma following Intravenous (IV) administration was described through a three-compartment pharmacokinetic model, which takes into account three specific areas where the drug can be distributed: the central compartment (blood and well-perfused organs), the second (poorly perfused tissues) and the third compartment (fat cells).
- Oral administration was described by a two-compartment model, taking into account absorption, elimination from the central compartment (blood and organs), and distribution into peripheral compartments (poorly perfused tissues).
- The research found that aminorex, when administered intravenously, had a large volume of distribution, an initially rapid decrease, and lengthy terminal elimination, which is the time taken for the drug to be expelled from the body.
- Similar results were observed for oral administration, with the addition of rapid absorption.
- The only effects detected on the horses at a dose of 0.03 mg/kg were temporary and central in origin, meaning they primarily affected the central nervous system. This was observed only following IV administration.
Conclusions
- The research concluded that aminorex has significant pharmacokinetic properties, having a large volume of distribution and a rapid initial decrease followed by an extended terminal elimination.
- However, the effects of aminorex were only detected in horses when the drug was administered intravenously.
Cite This Article
APA
Soma LR, Rudy JA, Uboh CE, Xu F, Snapp HM.
(2008).
Pharmacokinetics and effects of aminorex in horses.
Am J Vet Res, 69(5), 675-681.
https://doi.org/10.2460/ajvr.69.5.675 Publication
Researcher Affiliations
- New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA 19348, USA.
MeSH Terms
- Administration, Oral
- Aminorex / blood
- Aminorex / pharmacokinetics
- Aminorex / pharmacology
- Aminorex / urine
- Animals
- Area Under Curve
- Behavior, Animal / drug effects
- Central Nervous System Stimulants / blood
- Central Nervous System Stimulants / pharmacokinetics
- Central Nervous System Stimulants / pharmacology
- Central Nervous System Stimulants / urine
- Cross-Over Studies
- Female
- Half-Life
- Horses / metabolism
- Infusions, Intravenous
- Male
- Random Allocation
Citations
This article has been cited 3 times.- Maylin G, Fenger C, Machin J, Kudrimoti S, Eisenberg R, Green J, Tobin T. Aminorex identified in horse urine following consumption of Barbarea vulgaris; a preliminary report. Ir Vet J 2019;72:15.
- Maier J, Mayer FP, Brandt SD, Sitte HH. DARK Classics in Chemical Neuroscience: Aminorex Analogues. ACS Chem Neurosci 2018 Oct 17;9(10):2484-2502.
- Gutierrez J, Eisenberg RL, Koval NJ, Armstrong ER, Tharappel J, Hughes CG, Tobin T. Pemoline and tetramisole 'positives' in english racehorses following levamisole administration. Ir Vet J 2010 Aug 1;63(8):498.
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