Prednisolone hemisuccinate is a prohibited substance

Prednisolone is a corticosteroid and is a prohibited substance with a similar effect to hydrocortisone. Both prednisolone and hydrocortisone are commercially available as hemisuccinate (succinic acid) derivatives. The ester derivative, hydrocortisone hemisuccinate, is found in the preparation Solu Cortef while the similar ester, prednisolone hemisuccinate, is found in the well-known preparation Solu delta Cortef.

The term ester describes the link of the molecule succinate (succinic acid) to the corticosteroid (prednisolone) which is so-called ester linkage. This linked prednisolone hemisuccinate molecule has enhanced water solubility compared to prednisolone itself. Contained in injectable formulations, this ester derivative permits the intravenous administration of higher doses of prednisolone than otherwise possible.

When injected the prednisolone hemisuccinate is broken down in the body (the ester is hydrolysed) resulting in the release of prednisolone, the active corticosteroid molecule.

Prednisolone hemisuccinate is therefore not only an ester derivative but also a pro-drug of prednisolone. A pro-drug is defined as a precursor of a drug molecule that results in the formation of the drug (in this case prednisolone).

The hydrolysis of prednisolone hemisuccinate is not immediate. This ester derivative can be detected in both blood and urine for a period of at least 24 hours following the intravenous administration of a normal dose of a prednisolone hemisuccinate preparation (such as Solu delta Cortef).

As described in Rule 73.4, pro-drugs of prohibited substances and metabolites of prohibited substances are also prohibited substances. The administration of injected prednisolone hemisuccinate can therefore result in positive declarations on prednisolone hemisuccinate and/or prednisolone and/or known metabolites of prednisolone.


Methocarbamol is a muscle relaxant used to treat skeletal muscle spasms, with some effect on the central nervous system.  One of its actions is to block nerve impulses (such as pain sensations) to the brain. Methocarbamol is locally available as a human tablet preparation of commercial name “Robaxin”. It has therapeutic application in the horse and is used for the treatment of acute inflammatory and traumatic conditions of the skeletal muscle to reduce muscle spasm and effect muscle relaxation. Within the NHA Classification it is “Class 4 - substances which have a generally accepted veterinary (therapeutic) use in the racehorse but which have the potential to affect performance.”

Methocarbamol is a substance with an Asian Racing Federation screening limit and as member of this federation, the NHA has adopted this limit. This screening limit of 100 ng/ml in urine applies to: “Methocarbamol (restricted to single oral or IV treatment of no more than 5 grams)”

Within this guidance above it is clearly stated that it applies only to a single administration. The reason for this is that multiple dose of this substance have been reported to result in an accumulation of methocarbamol. This is non-predictable between different horses. This accumulation implies that multiple doses have an excretion time which is much longer than that of a single dose.

In oral studies there have been evidence of recycling during some trials. Recycling is when the preparation remains present in stable areas after administration (for example spilling, dripping or spitting by the horse), or when the substance is excreted in the urine and faeces and re-enters the horse. This can be reduced if the stable is frequently and thoroughly cleaned and with the realisation that it is not highly soluble in cold water. Recycling can be non-predictable between horses as well as in different stable environments.

It is recommended that Methocarbamol only be used as single dose treatment to the racehorse, with a detection time of about 48 hours (two days). With a detection of two days a withdrawal time period significantly longer than this must apply.  In isolation of this statement and guidance is the fact that a withdrawal period of several weeks must be applied when multiple doses are administered as part of a treatment regimen.

Consult your veterinarian with regards to suitable withdrawal periods. The NHA does not assume any legal, professional or other responsibility or duty whatsoever as to the accuracy of the data presented in this document. Please note that reliance on and use of the above information does not absolve or diminish a trainer or owner from being responsible for ensuring that the horse complies with the rules relating to the presence of prohibited substances when presenting a horse for a race.

Completion of the Vet Treatment Register by trainers

There is a misconception amongst trainers that the Vet Treatment Register (VTR) only has to be filled in by vets. Please note that this is NOT true. The VTR has to be completed whenever a horse receives ANY treatment. For example, if a vet dispenses a bottle of penicillin for the trainer to administer over the next 3 days, then the TRAINER must enter this administration in the VTR each time he treats the horse. The same would apply for ANY dispensed medication. Please note that a vet may only prescribe medication for 30 days. Any medication found in a trainers possession that was prescribed more than a month previously, shall be confiscated and the trainer fined. The same applies to expired medication. Please note that the use of dispensed medication does NOT apply to the 48 hour period before a race day. Only a vet may administer treatment 48 hours prior to a race day.

According to the protocol published, any administration of Lasix must be also be entered into the VTR by the Trainer as soon as it is administered. This becomes very important, should a horse get selected for Out of Competition sampling. If the Lasix treatment is not in the VTR at time of sampling, it will be considered not prescribed.

The other treatment that has to be recorded is any Extracorporeal Shockwave Therapy. The vet has to prescribe a programme for the horse (also entered in the VTR) and each time the horse is subsequently treated, this must be recorded by the trainer.

Trainers must also insist that the vet writes the VTR sequence number on the label of any drug that he dispenses. This will enable the NHA to link any medication found in a trainer’s possession to the correct VTR entry, which must detail all the dosage, route etc requirements.

Any dispensed medication not utilised, should be returned to the prescribing vet for disposal. Any chronic medication (i.e. treatment longer than two weeks for e.g. Ventipulmin dispensed for IAD in a horse), does not need to be recorded every day, with the proviso that the original dispensing instructions are clearly recorded in the VTR on the day corresponding to the sequence number on the label of the medication. Chronic medication must be renewed every 30 days and re-entered into the VTR with a new label and corresponding sequence number on the medication.

Please note that the old 24 hour rule has been changed and no longer applies. It is the trainer’s responsibility to ensure that his/her vet completes the VTR legibly as and when he treats the horse. Should the vet utilise his own VTR, then the trainer must file the copy that the vet leaves behind. This becomes very important when Out of Competition testing is done. The trainer MUST have available at all times, proof of any and all treatment administered to his horses. The discharge form from a hospital is also considered a treatment record in terms of the rules, to cover horses returning from surgery or hospitalization.

It is not necessary to record all administrations of cobalt containing preparations (for e,g, Vit B12) for Out of Competition testing, as cobalt will only be penalised when present on a race day. However, other unscheduled preparations (for e.g. Aspirin, which is available without prescription), must be entered into the VTR by the Trainer when administered. Beware of utilising any “Over the Counter” medication without consulting your vet regarding its composition and possible “prohibited substances” present in the formulation.

Dr D. P. Wheeler
Senior Veterinarian
24 August 2016

International Screening and Residue Limits and Asian Screening Limits

The NHA hereby advises it has adopted International Federation of Horseracing Authorities (IFHA) International Screening Limits (ISLs) to be applied in the control of therapeutic prohibited substances and also IFHA Residue Limits to control certain contaminants and environmental substances. In addition to this the NHA, as a signatory country of the Asian Racing Federation, has adopted several Asian Screening Limits (ASLs) for therapeutic prohibited substances. Details of these screening limits can be found in the section “International Screening Limits” in the “Laboratory” section of the website.

Dr S.S. de Kock
Laboratory Director
25 August 2016


Salicylic acid is a substance found in the normal feed of horses such as lucern and hay. During previous years large populations of racehorses from all over the world were screened for natural levels of salicylic acid which is ingested in such feeds. Considering the possible diets of horses and worst case scenarios, a single salicylic prosecution threshold was decided on an international basis. This International Federation of Horseracing Authorities (IFHA) threshold has been established with an extremely high probability that untreated horses on a variety of feeds will present levels far below this salicylic acid threshold.

The NHA has formally adopted this threshold:  “Salicylic acid…… 6.5 micrograms salicylic acid per millilitre in plasma” as shown on the website. A specimens is only declared a positive finding when the concentration of salicylic acid is accurately confirmed (full quantitative analysis is conducted as part of such a positive finding) to exceed this threshold, in accordance to Rule 73.4.4.  
It is know that Aspirin can be added to the feed of horses to acts as an analgesic and anti-inflammatory substance. Acetyl salicylic acid (Aspirin) is however a pro-drug of salicylic acid, implying that Aspirin will be converted to salicylic acid within the horse.  As Aspirin it is not a scheduled substance (in contrast to most analgesic and anti-inflammatory substances) it can be readily obtained by all. The administration of Aspirin to the racehorse must be recorded in the Veterinary Treatment Register of the horse. The use of Aspirin too close to race day is likely to result in salicylic acid prosecution. Be aware that guidance of the use of Aspirin products in the horse differ between different manufacturers.

Following the administration of a single dose of Aspirin a detection period of a two days applies (this is not a withdrawal time). Consult your veterinarian in regards to a suitable withdrawal period. The NHA does not assume any legal, professional or other responsibility or duty whatsoever as to the accuracy of the data presented in this document. Please note that reliance on and use of the above information does not absolve or diminish a trainer or owner from being responsible for ensuring that the horse complies with the rules relating to the presence of drugs and prohibited substances when presenting a horse for a race.


Adrenocorticotropic hormone, commonly called ACTH, is a protein hormone naturally produced in the horse. The function of ACTH is to stimulate and also regulate levels of the steroid hormone cortisol. Commercially available ACTH is a synthetically produced peptide hormone which is high similar in structure to ACTH produced naturally. As a prohibited substance in horseracing the use of synthetic ACTH is most commonly monitored and prosecuted by the increase which is observed the level of naturally produced hydrocortisone. As the hydrocortisone level increases beyond the international threshold, this is prosecuted as a prohibited substance offence.

There are also other approaches to detect the use of synthetic ACTH. One of these is based on the fact that synthetic ACTH corresponds to the structure of human ACTH. It can therefore be detected in the horse as the structure of this protein is somewhat different to naturally produced ACTH in the horse.  The NHA Laboratory is one of a few racing laboratories which have been active in the research of new approaches for the detection for synthetic administered ACTH in the race horse. During recent years ACTH administration trials were conducted on horses as part of such research at our Laboratory.  This research was formally presented at an international conference for horse racing chemists and veterinarians.

It must be noted that at least one web based sales company is selling a product which purport to contain the biochemically active molecule of ACTH. Several racing laboratories have already analysed this preparation. Such analysis however indicated that the active peptide ACTH is either not contained or is only contained in a very low concentration, certainly too low to effect the horse.


Erythropoietin (EPO) is natural occurring protein hormone which has the function to increase red blood cell production in the horse. Natural EPO can be supplemented by the administration of several different forms of human EPO to the horse. At the NHA Laboratory the screening of  human EPO in horse specimens is being undertaken employing a sophisticated immuno-detection screening methodology which is widely reported as the most accurate and sensitive currently available to the racing industry.  A highly attractive aspect about this is the wide range of EPO types which are covered, as was been confirmed by EPO administration and research studies at racing laboratories.  Included in the effective coverage of the screen is conventional EPO forms such as Epogen, Eprex, Epoetin-alpha, Epoetin-beta and Procrit and even longer acting EPO types called darbepoetin alfa (Aranesp, DPO) and CERA (PEG Epoetin-beta, MirCERA).

Growth Hormone (GH) refers to a natural hormone within the horse which is anabolic and which has the effect to enhance cell growth and cell recovery. In addition to this natural occurring equine GH there are a range of synthetic GH’s from several animal species which are active in the horse. These include a modified form of equine GH, bovine (cattle) GH and porcine (pig) GH. The NHA Laboratory employs a sensitive immune-detection screening approach which was shown effective in detecting the use these hormones by means of the measurement of the amount of the messenger protein “IGF-1”. The screening methodology measures the IGF-1 concentration against the level which is normal in the horse and can also detect the use of and some IGF-1 analogues and synthetic IGF-1 forms. The NHA Laboratory was a few years ago, in partnership with a few other countries, instrumental in conducting important research into suitable screening methodologies and validating these screening approaches.

The NHA recognises the threat which these Class 1, Forbidden Substances pose to the integrity of racing and the welfare of the horse and for this reason these screening methods have been in place at the NHA for many years.


Most conventional medication contain drug substances which are small chemical molecules. Many of these can affect the horse and hundreds of these are routinely screened for by the NHA Laboratory. Many of these newer generation substances which are prohibited and which are of concern are peptide and proteins similar to those found naturally in the horse. This Laboratory is actively involved in a program to extend the screening of racing and out of competition specimens for an increasing number of peptide and protein substances which can affect the horse. These are the future drugs of concern, most of these substances are classified as Class 1, Forbidden Substances within the Rules of the NHA.


Non-steroidal anti-inflammatory drugs (NSAID’s) are pharmaceutical substances which are prescribed for the treatment of muscle and joint injury, pain, swelling and inflammation. In the form of tablets, capsules and injections these can also be obtained by medical prescription or as dispensed by a pharmacist. These non-steroidal anti-inflammatory drugs contain however also be obtained in certain products which do not have a pharmaceutical schedule which are sold in shops without a prescription. The purchase and use of such preparations in racehorses can results in positive findings for these prohibited substances. These preparation are normally gel and plaster packs with trade names such as:
  • Voltaren Emulgel containing Diclofenac
  • Fastum containing Ketoprofen
  • Transact containing Flurbiprofen

It is important that care is taken when purchasing such substances and when using such preparations on horses. Consult with your veterinarian in this regard.

Reports of the ALLEDGED use of prohibited
substances SUCH AS ACTH, ITPP AND EPO in racing

It has come to our attention that several web based preparation supplier companies are selling a variety of equine products. These are allegedly sourced by some local racehorse trainers and owners and these are administered to racehorses. Many of these companies have only website addresses as their only point of contact or do not have a physical address or only have an overseas address which cannot be verified.
Several such preparations were sourced by the NHA and these were screened for the presence of prohibited substances at the NHA Laboratory. The analysis of these products indicated that these preparations do not contain the components that are claimed on the label. Prohibited substances are not present within these preparations.

It is important to be aware that these label and web advertisement claims are inaccurate and misleading. The use of these products does not constitute the administration of the indicated prohibited substance. This would result in such false claims being made by trainers and owners which use these products. 
The findings by our Laboratory that the label claims of these products are not correct is substantiated by similar testing of these and other such preparations at other racing laboratories. The findings at these laboratories mirror ours.  Some examples of such substances include ITPP, Aranesp (a form of Erythropoietin/EPO), ACTH and TB-500 (a peptide drug).  Within some of these products which were tested the claimed vitamins and amino acids have been shown present, but not the claimed major component.  In some products the claimed prohibited substance is present but is contained in a much lower concentrations than indicated or at a level much lower than would affect the horse.
The pricing of many of these products are suspiciously low considering the amount of the chemical or biochemical substance which the product is claimed to contain. The storage conditions specified for the product is often not consistent with the stability of this actual substance. The labelling is also not at all consistent of a legally registered pharmaceutical product of reputable quality and verifiable content and potency. Be aware of recent reports that some of these web based companies are currently actively being investigated and warned by the FDA in the USA for non-compliance which will result in serious action.
Note that several equine studies have been conducted on many of the actual, scientifically verified pure substances which some of these products claim to contain and there is evidence that several of these substances do not result in therapeutic benefit to the horse. 
The NHA Laboratory, as an active member of the Association of Official Racing Chemists and the International Federation of Horseracing Authorities, is aware of the range of prohibited substance of concern to racing on a worldwide and also local basis and continue to investigate such substances as part of the screening conducted on racehorse specimens. 
Where and when preparations such as those describe above are sourced these are thoroughly investigated and researched at our Laboratory.

Dr S. S. de Kock
Laboratory Director
17 August 2016

The Judgment and the Inquiry Board’s decision in respect of the penalties imposed in the matter involving trainer Mr Paul Peter are available for download.
To download a copy of the Judgment, click here. (24 KB)
To download a copy of the Inquiry Board’s decision in respect of the penalties imposed, click here. (301 KB)


Cobalt is naturally found in all animals and animal feed and is considered an essential dietary trace element and micronutrient. Cobalt deficiency is not observed in horses in the wild and the normal diet of horses in combination with the usual prescribed vitamin supplementation should supply the horse with sufficient cobalt for its well-being and health. Cobalt is classed as a ’heavy metal’ and is a structural component of vitamin B12 (cobalamin). This vitamin is involved in the normal functioning of the brain and nervous system and in the final stages of red blood cell formation and maturation. All of cobalt’s potential physiological effects in the horse have not yet been determined; however, high doses can present severe toxic effects and be very detrimental to the health of the horse. 
Evidence suggests that cobalt preparations are being used inappropriately in racehorses in some racing jurisdictions. As cobalt is naturally present in equine biological samples such as blood and urine, it was decided that the introduction of an international threshold for cobalt will be necessary to facilitate the control of misuse in racehorses. 
Trainers are advised that the International Federation of Horseracing Authorities (IFHA) has set an international threshold of 0.1 microgram per millilitre cobalt in horse urine. The NHA, as a signatory country of the IFHA, has now adopted this threshold in its rules. This decision was made following a survey which showed that natural levels of cobalt in racehorses within South Africa correspond to those observed in other countries and that the threshold can be applied to the local population.  In future any finding of cobalt above this international threshold will be a Class 3 offence.
A large range of registered oral and injectable veterinary supplements which contain vitamin B12 (cobalamin) are available for use in the horse. The administration of any of these could give rise to an elevation of total cobalt levels in blood and urine. 
It is recommended that supplemental cobalt from any source, including registered cobalt containing supplements and vitamin B12 (cobalamin), not be administered to the horse within at least two full days prior to race day. Higher doses than those indicated by the product and also repeated administrations may require longer elimination periods. Note that reliance on and use of this guidance does not absolve or diminish a trainer or owner from being responsible for ensuring that the horse complies with the rules relating to the presence of drugs and prohibited substances when presenting a horse.


At a meeting of the National Board held on 30 July 2015, it was agreed that the Guidelines for Classification of Prohibited Substances would be amended by the addition of the following substance classifications:
CARBON DIOXIDE (Total available Carbon Dioxide)
Accordingly, Carbon Dioxide is classified as a Class 2 substance, a substance which has an obvious effect on a horse.  The internationally agreed threshold / concentration applied by the NHA for Carbon Dioxide is 36 millimoles available Carbon Dioxide per litre in plasma.
Cobalt is classified as a Class 3 substance, a substance which has the potential to affect the performance of the horse.  The internationally agreed threshold / concentration applied by the NHA for Cobalt is 0.1 microgram total cobalt per millilitre in urine.


 African Horsesickness Vaccinations

Please note that the African Horsesickness Vaccination Scedule has been amended with immediate effect. All foals must be vaccinated against African Horsesickness two times between the ages of 6 and 18 months.  These vaccinations must not be less than 30 days apart.  (Previously, the two vaccinations were not to be less than 90 days apart.)




Please read the link below pertaining to containment in the W Cape Surveillance Zone following the death of a horse, which tested positive for African horse sickness.  The Equine Health Fund and Equine Research Centre are supporting the WC DAFF in the investigation of the outbreak. All owners with horses planning to travel to the upcoming sales, or shows, from the containment zone should confer with their treating vet and the state vet for movement certificates. 
Further information will be provided as soon as it becomes available. Queries should be directed to Bev Parker (082 578 7044) or Camilla Weyer (083 710 2408). 
Click here for the link to the Notice from the W Cape Department of Agriculture.

Click here for the link to the Notice from the W Cape Department of Agriculture.



The National Horseracing Authority believes that all horses deserve to be treated with care and dignity when their racing career comes to an end. Thoroughbred horses are refined athletes and do excel in order equine sports such as polo, show jumping, dressage and equitation. However, they are not designed to withstand meagre or rural conditions and every effort must be made to prevent Thoroughbreds from ending up in circumstances where they would be neglected or abused.

For this reason, The National Horseracing Authority has promulgated a new rule to specify how racehorses must be treated once they have finished racing. The new rule recognises that all Owners have a responsibility towards their horses, whether they have been successful or unsuccessful, and that Owners have certain obligations to make sure that their horses do not end up in unpleasant conditions.

Whilst The National Horseracing Authority is mindful that the additional burden of responsibility now placed on the Owner may be inconvenient, it is certain that everybody will agree that these magnificent animals which provide so much excitement and provide significant economic benefits, deserve careful consideration when their time as a racehorse is over.