Banned substances – SJ Case Study

Introduction

This report evaluates the case of Genius di San Georgio (Genius), a 9 year old horse who took part in the CSI3* Show Jumping event in Arezzo, Italy during 5-10/4/05 achieving 1st place at 130cm, and 5th in both 135cm and 140cm courses (FISE, 2006).  Genius was ridden by the Person Responsible (PR) Bryan Mascenti, and was selected for blood sampling on 9/4/05.  The sample was found to contain phenylbutazone and oxyphenbutazone which are non-steroidal anti-inflammatory drugs (NSAID’s) acting, inter alia, on the locomotor system, and theophylline which is a xanthine acting, inter alia, on the respiratory system.  These prohibited substances are graded ‘1’ (having a relative high potential to affect the performance of the horse) and defined as a ‘cocktail’ by the Fédération Equestre Internationale (FEI).  The PR claimed to have no knowledge of who could have given Genius the prohibited substances, and that no medical treatment was prescribed to the horse prior to the Event. The horse and PR were disqualified from the Event, and any prize money forfeited.  The PR was suspended from competition for five months with immediate effect, fined CHF 1500 (approx. £660), and ordered to contribute CHF 1000 (approx. £440) towards legal costs of the judicial procedure (FEI, 2006).

Scientific Background and Physiological Implications

Phenylbutazone and Oxyphenbutazone (Bute) provide analgesic, antipyretic and anti-inflammatory effects via the inhibition of the formation of inflammatory mediator, prostaglandin E2.  Bute is commonly used for palliative relief of lameness, muscle soreness, bone and joint problems. Bute may be given intravenously or per os and is effective within 1-2 hours. The effects of clinical dosage last for approximately 24 hours, although elimination rates vary, taking up to 8 days.  Prolonged use of Bute can cause oral and gastrointestinal ulceration, haemhorrages, and renal damage which could lead to renal failure and even death (Kollias-Baker and Cox, 2004).  Theophylline is a naturally occurring xanthane alkaloid which acts mainly as a bronchodilator and smooth muscle relaxant (used therapeutically for chronic obstructive pulmonary disease and bronchial asthma); it also has modest diuretic and sympathomimetic properties.  The exact mode of action remains unclear, although theophylline does cause inhibition of phosphodiesterase with a resultant increase in intracellular cyclic AMP and release of endogenous adrenaline. Theophylline has a narrow therapeutic index, so its use must be monitored to avoid toxicity. Side effects in horses are generally dose related and may include: nervousness, excitability, tremors, diaphoresis, tachycardia, and ataxia. Seizures or cardiac dysrhythmias may occur in severe intox­ications. Detection of residues of theophylline for a week or longer after clinical dosage is not uncommon (Harkins et al., 1988).

FEI Drug Testing Policy

The FEI Medication Control Program aims to prevent unfit horses participating in competition (with the help of medicines), and is based on a list of prohibited substances.  Post-competition samples of urine and/or blood are taken from winning and random non-winning horses and split into an A and B portion.  Sample A is screened at an FEI approved laboratory, and if labelled positive, the findings are reviewed by the FEI Medication Sub Committee who advise whether to proceed with the case.  The presence of a prohibited substance is presumed to be a deliberate attempt of the PR to affect the performance of the horse (FEI, 2006).  The PR had the right to confirmatory analysis of Sample B, which in this case was waived, and did not contest the accuracy of testing methods, results and positive findings.