Disposition of human drug preparations in the horse. II. Orally administered fencamfamine.

The research article discusses a method to detect the stimulant drug, fencamfamine, in horse urine and notes that human methods of detection may result in false negatives.

Research Methodology

• The researchers employed a gas chromatographic method – an analytical method used to separate and analyze compounds that can be vaporized without decomposition – to measure urinary levels of the drug fencamfamine and some of its metabolites.
• A total of four horses were given 100 mg of fencamfamine orally.
• The team attempted to detect the parent drug in the urine of these horses. In addition, they performed enzymatic hydrolysis (a process that uses water to break down a compound) on the urine samples to identify metabolites of fencamfamine.

Findings

• The parent drug, fencamfamine, could not be detected in the urine of the horses. This indicates that the drug is either fully metabolised or not excreted through urine.
• Post enzymatic hydrolysis, the researchers found that the primary human metabolite known as N-desethylated fencamfamine accounted for only 1% of the dose after 12 hours. This indicates that the metabolite occurs in very low concentrations in equine urine or the drug is metabolised differently in horses compared to humans.
• They also found that the major metabolites in horses were conjugated parahydroxylated compounds, accounting for 18% of the dose. These are specific chemical compounds that are product of metabolic processing in horses and were found in relatively higher concentrations.

Implications

• This study reveals that common methods used to detect the presence of the drug fencamfamine in human urine might not be as reliable when applied to horse urine. This has implications for doping control measures in equestrian sports, suggesting that current detection methods may lead to false negative results.
• Researchers suggest that more tailored techniques may be necessary for detecting drug use in horses, considering the unique ways in which they metabolize certain substances compared to humans.