Systematic analysis to assess the scientific validity of the international residue limits for caffeine and theophylline in horse-racing.
Abstract: Based on their performance-enhancing potential, caffeine and theophylline are prohibited substances in equine sports. Residues in horses can be caused by wilful application or by unintended uptake of contaminated feed. The International Federation of Horseracing Authorities recently introduced international residue limits (IRLs) to facilitate the discrimination between pharmacological relevant and irrelevant concentrations in doping samples. The objective of this study was to investigate the scientific validity of these IRLs. A systematic analysis was performed to assess the IRLs by different statistical approaches using published pharmacokinetic data. 31 out of 218 potentially relevant publications met the inclusion criteria. Thereby, both IRLs were found to be appropriate for the exclusion of the presence of a relevant pharmacological effect after a wilful application. The IRL of theophylline was also determined to be suitable for the prevention of positive doping tests caused by the ingestion of contaminated feed. In contrast, the IRL of caffeine is not suitable to prevent positive doping test caused by the ingestion of more than 10 mg caffeine per day per horse with contaminated feed. The lack of corresponding regulation for paraxanthine, a major active metabolite of caffeine and theophylline, was recognised as a substantial shortcoming of the current system, rendering both IRLs incomplete.
© British Veterinary Association 2019. No commercial re-use. See rights and permissions. Published by BMJ.
Publication Date: 2019-08-13 PubMed ID: 31409753DOI: 10.1136/vr.105404Google Scholar: Lookup
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- Journal Article
- Systematic Review
Summary
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The research investigates the international restrictions in horse racing concerning the presence of caffeine and theophylline, substances known to enhance performance. The study scrutinizes the scientific validity of these restrictions and suggests that while they’re generally effective, they have some shortcomings.
Overview of Research
In this study, the researchers aim to determine the scientific soundness of the International Federation of Horseracing Authorities’ (IFHA) restrictions on caffeine and theophylline residues in horse racing. These substances enhance horses’ performances, but they might also get into horse systems unintentionally through contaminated food.
Research Methodology
- The researchers adopted a systematic review, scrutinizing previously published pharmacokinetic data to evaluate the IFHA’s international residue limits (IRLs).
- From 218 potential publications, 31 met the study’s strict inclusion criteria and were included for detailed analysis.
Findings
- Both current IRLs were found appropriate for ruling out a meaningful pharmacological effect of willful substance application.
- The theophylline IRL was also found suitable to prevent positive doping test results from consuming contaminated feed.
- However, the established IRL for caffeine proved ineffective in preventing positive tests if a horse consumes more than 10 mg of caffeine per day via contaminated food.
- The researchers also identified a significant oversight: there is no specific regulation for paraxanthine, a major active metabolite of caffeine and theophylline. This omission rendered the existing IRLs incomplete.
Implications
- The study identifies possible to gaps in current regulations around caffeine and theophylline in horse racing, prompting the need for the IFHA to revise its present guidelines.
- It is particularly necessary to create appropriate residue limits for paraxanthine, to account for the metabolization of caffeine and theophylline.
- The findings also point to the necessity of more strict controls to prevent possible contamination of horses’ food with prohibited substances.
Cite This Article
APA
Hertzsch R, Richter A.
(2019).
Systematic analysis to assess the scientific validity of the international residue limits for caffeine and theophylline in horse-racing.
Vet Rec, 185(8), 230.
https://doi.org/10.1136/vr.105404 Publication
Researcher Affiliations
- Institute of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany robert.hertzsch@uni-leipzig.de.
- Institute of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany.
MeSH Terms
- Animals
- Caffeine / pharmacokinetics
- Doping in Sports / legislation & jurisprudence
- Drug Residues / standards
- Horses
- Internationality / legislation & jurisprudence
- Reproducibility of Results
- Theophylline / pharmacokinetics
Conflict of Interest Statement
Competing interests: None declared.
Citations
This article has been cited 2 times.- Roccaro M, Rinnovati R, Stucchi L, La Rocca F, Cascio G, Peli A. Survey on 9 years of anti-doping controls in horse races in Italy. Equine Vet J 2025 Nov;57(6):1592-1599.
- Manrique-Suárez V, Gutiérrez N, Hidalgo-Gajardo A, Gonzalez-Horta EE, Hugues F, Cabezas I, Contreras MA, Montesino R, Soares Alves M, Reyes F, Parra NC, Gädicke L'Huissier PC, Toledo JR. Development of an indirect ELISA for the serologic detection of bovine viral diarrhea virus based on E2 antigen sub-genotypes 1b, 1e, and 1d. Trop Anim Health Prod 2024 Oct 2;56(8):314.
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