Thoroughbred horse owners, trainers and/or veterinarians who are responsible for
causing or failing to guard against an administration of a bisphosphonate to a racehorse
less than four years old will be investigated for a violation of 9 NYCRR § 4043.12(c) for
which a fine of $25,000 may be imposed and the person’s occupational license shall be
The New York State Gaming Commission has determined that there is no generally
accepted medical use of a bisphosphonate in a racehorse that is less than four years
old; that bisphosphonates are “other doping agents” within the meaning of 9 NYCRR §
4043.12(c)(1); and that any such administration shall violate 9 NYCRR § 4043.12(c).
This limitation applies to any Thoroughbred horse engaged in activities, including
training, related to competing in pari-mutuel racing in New York. This includes without
limitation any horses that are training outside the jurisdiction to participate in racing in
New York who subsequently race in New York and all horses that are training in the
An administration occurs, within the meaning of 9 NYCRR § 4043.12(c), whenever a
substance is introduced into the body of a horse, not only by deliberate introduction of
the substance, but also by unintentional acts or omissions.
Summary of Advisory Warning
Any administration of a bisphosphonate to a racehorse less than four years old is an
unacceptable practice because of an unacceptably high risk of serious injury or death
from deleterious effects on bone growth and strength as a consequence of such use.
Trainers are responsible to guard their horses and to prevent the administration of any
substance in violation of Commission rules pursuant to 9 NYCRR § 4043.4(a). Owners
and veterinarians are responsible for their acts or omissions that cause such violations.
A violation of this rule shall result in exclusion of the horse from racing and the license
revocation of any responsible person. 9 NYCRR § 4043.12(e). No bisphosphonate shall
be administered to a horse without a veterinary prescription. 9 NYCRR § 4043.16.
Therapeutic Exception for Certain Horses
It is not a violation to administer a bisphosphonate to a racehorse pursuant to a valid
therapeutic, evidence-based treatment plan. A therapeutic, evidence-based treatment
plan is a planned course of treatment written and prescribed by an attending
veterinarian before the horse is treated that describes the medical need of the horse for
the treatment, the evidence-based scientific or clinical justification for using the
bisphosphonate, and a determination that recognized therapeutic alternates do not
exist. 9 NYCRR § 4043.12(c)(3). This exception does not permit bisphosphonate
possession on the grounds of a licensed racetrack in New York. It is strongly
recommended that any such plan be submitted to the Equine Medical Director before
any use, including for horses that might ship into New York.
Basis of Advisory Warning
Bisphosphonates are substances used to treat osteoclast-mediated osteoporosis in
humans. Bisphosphonates have a high affinity for bone where they inhibit calcification
and hydroxyapatite breakdown, suppress bone resorption and their intracellular
accumulation is cytotoxic to osteoclasts.1 The use of bisphosphonates in younger
animals is contraindicated because bisphosphonates inhibit osteoclast-mediated bone
resorption, resulting in the accumulation of trabecular microdamage that can
compromise the mechanical and regenerative properties of bone.
2 These effects
predispose affected bone to delayed union and fractures.
Tiludronate disodium (Tildren®) and Clodronate disodium (Osphos®) are two firstgeneration bisphosphonates currently approved by the FDA for treatment of equine
navicular disease in horses four or more years old. The manufacturer’s guidelines for
both products include the following indications, warnings and precautions:
Tildren® / Osphos® is indicated for the control of clinical signs associated
with navicular syndrome in horses. The safe use of Tildren® /Osphos®
has not been evaluated in horses less than 4 years of age. The effect of
bisphosphonates on the skeleton of growing horses has not been studied;
however, bisphosphonates inhibit osteoclast activity which impacts bone
turnover and may affect bone growth.
Further, the Equine Medical Director has consulted with other leading equine
veterinarians, who concur that the use of bisphosphonates to treat race horses less
than four years old is not a generally accepted veterinary practice.
Given the scientific evidence that bisphosphonates are potentially harmful to the normal
modeling of bone in horses less than four years of age, the absence of FDA approval or
manufacturer’s label recommendations for the use of Tildren® / Osphos® in any horse
less than four years old, and consultation with other leading equine veterinarians, the
Commission has determined that an administration of a bisphosphonate to a racehorse
less than four years old shall be investigated as an unlawful and prohibited practice.
No drug may be administered, under any circumstances, to a racehorse engaged in
activities, including training, related to participating in pari-mutuel racing in New York,
without appropriate veterinary approval. 9 NYCRR § 4043.16. This requires a valid
veterinarian-client-patient relationship between an attending veterinarian, the horse
owner (who may be represented by the trainer or other agent) and the horse, including:
(1) the veterinarian, with the consent of the owner, has accepted responsibility for
making medical judgments about the health of the horse;
(2) the veterinarian has sufficient knowledge of the horse to make a preliminary
diagnosis of the medical condition of the horse;
(3) the veterinarian has performed an examination of the horse and is acquainted
with the keeping and care of the horse;
(4) the veterinarian is available to evaluate and oversee treatment outcomes, or has
made appropriate arrangements for continuing care and treatment;
(5) the relationship is maintained by veterinary visits as needed, and
(6) the veterinary judgments of the veterinarian are independent and are not dictated
by the trainer or owner of the horse.
9 NYCRR 4043.16(a). Further, no prescription drug may be administered except as
prescribed by an attending veterinarian. 9 NYCRR § 4043.16(b).
According to the manufacturers of Tildren® / Osphos®, the use of bisphosphonates is
not recommended in any horse with conditions affecting renal function or mineral or
electrolyte homeostasis, and bisphosphonates should not be administered concurrently
with non-steroidal anti-inflammatory drugs (e.g., phenylbutazone, flunixin) as this may
increase the risk of renal toxicity and acute renal failure. If treatment for discomfort is
required after bisphosphonate administration, a non-NSAID treatment should be used.
Equine Medical Director Scott E. Palmer, V.M.D., therefore, recommends that no
racehorse be treated with Tildren® / Osphos® or similar bisphosphonate substances,
except after the attending veterinarian has taken into account the foregoing information.