Besides being the second in popularity only to soccer as a spectator sport, Greyhound racing in the UK is an important medium for gambling, typically accounting for around 20% of turnover in high street betting shops. Use of any medication can potentially affect a dog's race performance. Although the distrinction between legitimate therapy and unacceptable drug administration may at times be a fine one, to preserve the perceived integrity of the sport as a gambling medium, it is necessary that the competing dogs should be seen to be 'drug free'. Most Greyhound racing in the UK takes place under the regulatory umbrella of the Greyhound Board of Great Britain (GBGB), which places restrictions on the use of medication in race dogs. No such restrictions apply to the use of medication in Greyhound racing in the so-called independent sector. However, this does not imply that veterinary surgeons treating such Greyhounds are free to prescribe for them without restraint, as the welfare of the Greyhounds in their care must always be the overarching concern. The remainder of this article concentrates on the GBGB sector. 

Rules of Racing
The GBGB 'Rules of Racing' do not specifically prohibit the use of particular substances. However, they do stipulate that 'A Greyhound when taking part in a Race or Trial must at that time be free of medicines, tonics or substances that could affect its performance or wellbeing, the origin of which can not be traced to normal and ordinary feeding.' The Anti-Doping & Medication Control review group has suggested relaxing the restrictions on the use of some topical applications used in first aid, but at time of writing the 'Rules of Racing' have not been amended to allow this. There are some veterinary medicinal products (VMPs) which can be administered to Greyhounds in any circumstances. Rule 217 of the GBGB’s ‘Rules of Racing’ permits the use of:

• ‘medicinal products which have been authorized by the Veterinary Medicines Directorate for the suppression of a bitch’s season, prescribed by a veterinary surgeon’
• ‘medicinal products which have been authorized by the Veterinary Medicines Directorate as anti-parasitic drugs (for internal/external) parasites or as vaccines in canines.’

Apart from these few notable exceptions, Rule 217 requires that:

• ‘Any tonics, medicaments or other substances administered or applied to a Greyhound by a Trainer or Veterinary Surgeon shall be duly recorded in the Trainer’s Greyhound treatment book, and that that Greyhound must not race or trial for seven days thereafter.’

The GBGB also advises that:

• ‘Although most prohibited substances will clear the Greyhound’s system within seven days, some products may still be detectable more than seven days after administration. However, it is the responsibility of owners and trainers to satisfy themselves in every case that a Greyhound complies with Rule 217 when taking part in a race or trial.’

Therefore, it is incumbent upon the prescribing veterinary surgeon to accurately advise the owner and/or trainer of a Greyhound under their care as to how long that Greyhound must be withheld from trialling and racing.

• Particular problems arise with the use of depot or other long-acting injectable medicines. It is not always possible to give guidance on the excretion times of specific medicines as, since this information is not legally required to be furnished by the manufacturer as part of an application for a marketing authorization, it may simply not be known. The decision to administer such a preparation should be carefully considered as it may result in either a positive drug test or a prolonged lay-off time.
• Delayed absorption and excretion may occur following intramuscular injection. Since absorption depends on vascularity and lipid solubility, inadvertent injection into fatty tissue or between fascial planes may result in prolonged excretion.
• Lipid-soluble substances, such as corticosteroids and local anaesthetics, may be well absorbed following, for example, intra-articular injection and may be detectable in urine. Topical non-steroidal anti-inflammatory drugs (NSAIDs) may be absorbed through the intact skin, leaving detectable residues in urine.

Generally, the amount of a substance found in a sample of urine or blood taken from a competing Greyhound is irrelevant in determining whether or not there has been a breach of the ‘Rules of Racing’. The detection of a prohibited substance in any quantity is likely to initiate a Stewards’ Inquiry.

Summary
In summary, when prescribing for racing Greyhounds, the attending veterinary surgeon should:

• Adhere strictly to datasheet recommendations as far as possible
• Follow the prescribing cascade if this is not possible
• Advise owners and trainers not to race dogs for at least 7 days after treatment, or longer if deemed necessary.