Important information regarding the use of Regumate Equine 2.2 mg/ml Oral Solution for Horses

The British Horseracing Authority’s (BHA) press release of 21st September states that their recent research has confirmed that current UK stocks of Regumate Equine, which contain the active ingredient altrenogest, also contain trendione, an anabolic steroid which is a prohibited at all times substance under Schedule (G) 1 of the BHA Rules of Racing.

If horses in training for racing test positive for trendione, the consequences of breaching these Rules of Racing may be severe and therefore their advice is that all BHA licensed premises, i.e. racehorse training stables, immediately cease all use of Regumate Equine and remove all stocks from their premises to avoid accidental administration.

Further discussion with the BHA’s Director of Health and Welfare confirms that it is not current BHA policy to restrict the legitimate use of Regumate Equine, on veterinary advice, for broodmares permanently retired from racing at stud farms, which are not licensed premises. However, until BHA completes its research in this field and formulates any necessary further specific advice, it is our opinion that in order to reduce the risk of triggering an unintended trendione blood test at a later stage, stud farms should:

• Restrict the use of Regumate Equine to broodmares that have permanently retired from racing, being careful not to treat fillies out of training that are intended to or may return to racing and those that may be sold or change location and may unpredictably return to racing.
• Not to use Regumate Equine in foals, yearlings or horses in or waiting to enter pre-training, of either sex, for whatever reason.
• Maintain secure storage of Regumate Equine supplies on stud farms to minimise the risk of its accidental use.
• Restrict access to and the administration of Regumate Equine to specifically selected and trained staff to minimise the risk of its accidental use.
• Maintain detailed records of mares treated with Regumate Equine to provide evidence at a later date should a positive trendione blood test occur and require explanation.

Currently, it remains unknown whether foals born to mares whose pregnancies have been supported by the use of Regumate Equine might have acquired blood trendione levels by cross-placental transfer, sufficient to test positive if tested when individuals enter licenced premises for training for racing as yearlings or two-year-olds. We understand that no trendione positive tests have yet been encountered during BHA testing of racehorses, significant numbers of whom will have been born from mares who were treated with Regumate Equine during their pregnancies. This suggests that this risk is very low for foals born from treated mares, however we believe that BHA will conduct further research into this possibility and give more accurate advice, when results become available.

It also remains unknown whether other formulations of altrenogest available in UK, e.g. Regumate Porcine (MSD) and specially compounded altrenogest do or do not contain trendione. Until BHA provide further advice following specific testing, we recommend that if studfarms have used or intend to use these products, we recommend that they follow our advice above as for Regumate Equine.

Professor Sidney Ricketts, LVO, BSc, BVSc, DSc, DESM, DipECEIM, FRCPath, FRCVS.

Dr James Crowhurst, MA, VetMB, MRCVS.

TBA Joint Veterinary Advisors

28th September 2018