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for control of clinical signs
associated with Navicular Syndrome
in horses 4 years of age and older
* Freedom of Information Summary, Original New Animal Drug Application, approved by FDA under NADA # 141-427, for OSPHOS. April 28, 2014.
Dechra Veterinary Products US and the Dechra D logo are registered trademarks of Dechra Pharmaceuticals PLC. © 2019 Dechra Ltd.
CAUTION: Federal law restricts this drug to use by or on the order of licensed veterinarian.
As with all drugs, side effects may occur. In ﬁeld studies and post-approval experience the most common side effects reported were signs of discomfort, nervousness,
and colic. Other signs reported were: renal insufﬁciency/failure, anorexia, lethargy, hypercalcemia, behavioral disorders, hyperkalemia, hyperactivity, recumbency,
hyperthermia, injection site reactions, muscle tremor, urticaria, hyperglycemia, and fracture. In some cases, death has been reported as an outcome of these
adverse events. The safe use of OSPHOS has not been evaluated in horses less than 4 years of age or breeding horses. OSPHOS should not be used in pregnant or
lactating mares, or mares intended for breeding. NSAIDs should not be used concurrently with OSPHOS. Concurrent use of NSAIDs with OSPHOS may increase
the risk of renal toxicity and acute renal failure. Use of OSPHOS in patients with conditions affecting renal function or mineral or electrolyte homeostasis is not
recommended. Refer to the prescribing information for complete details or visit www.dechra-us.com.
Manufactured for: Dechra Veterinary Products
7015 College Blvd., Suite 525, Overland Park, KS 66211
© 2019 Dechra Ltd. OSPHOS is a registered trademark of Dechra Ltd.
All rights reserved. Approved by FDA under NADA # 141-427
For use in horses only.
Brief Summary (For Full Prescribing Information, see package insert)
CAUTION: Federal (USA) law restricts this drug to use by or on the order
of a licensed veterinarian.
DESCRIPTION: Clodronate disodium is a non-amino, chloro-
containing bisphosphonate. Chemically, clodronate disodium is (dichloro-
methylene) diphosphonic acid disodium salt and is manufactured from
the tetrahydrate form.
INDICATION: For the control of clinical signs associated with navicular
syndrome in horses.
CONTRAINDICATIONS: Horses with hypersensitivity to clodronate disodi
um should not receive OSPHOS. Do not use in horses with impaired renal
function or with a history of renal disease.
WARNINGS: Do not use in horses intended for human consumption.
HUMAN WARNINGS: Not for human use. Keep this and all drugs out of
the reach of children. Consult a physician in case of accidental human
PRECAUTIONS: OSPHOS has been associated with renal toxicity.
Concurrent administration of other potentially nephrotoxic drugs should
be approached with caution and renal function should be monitored.
Use of bisphosphonates in patients with conditions or diseases affecting
renal function is not recommended. Horses should be well-hydrated
prior to and after the administration of OSPHOS due to the potential for
adverse renal events. Water intake and urine output should be monitored
for 3-5 days post-treatment and any changes from baseline should elicit
further evaluation. As a class, bisphosphonates may be associated with
gastrointestinal and renal toxicity. Sensitivity to drug associated adverse
reactions varies with the individual patient. Renal and gastrointestinal
adverse reactions may be associated with plasma concentrations of the
drug. Bisphosphonates are excreted by the kidney; therefore, conditions
causing renal impairment may increase plasma bisphosphonate
concentrations resulting in an increased risk for adverse reactions.
Concurrent administration of other potentially nephrotoxic drugs should
be approached with caution and renal function should be monitored. Use
of bisphosphonates in patients with conditions or diseases affecting renal
function is not recommended. Administration of bisphosphonates has
been associated with abdominal pain (colic), discomfort, and agitation
in horses. Clinical signs usually occur shortly after drug administration
and may be associated with alterations in intestinal motility. In horses
treated with OSPHOS these clinical signs usually began within 2 hours
of treatment. Horses should be monitored for at least 2 hours following
administration of OSPHOS.
Bisphosphonates affect plasma concentrations of some minerals and
electrolytes such as calcium, magnesium and potassium, immediately
post-treatment, with effects lasting up to several hours. Caution should
be used when administering bisphosphonates to horses with conditions
affecting mineral or electrolyte homeostasis (e.g. hyperkalemic periodic
paralysis, hypocalcemia, etc.). The safe use of OSPHOS has not been
evaluated in horses less than 4 years of age. The effect of bisphospho
nates on the skeleton of growing horses has not been studied; however,
bisphosphonates inhibit osteoclast activity which impacts bone turnover
and may affect bone growth.
Bisphosphonates should not be used in pregnant or lactating mares,
or mares intended for breeding. The safe use of OSPHOS has not
been evaluated in breeding horses or pregnant or lactating mares.
Bisphosphonates are incorporated into the bone matrix, from where they
are gradually released over periods of months to years. The extent of
bisphosphonate incorporation into adult bone, and hence, the amount
available for release back into the systemic circulation, is directly related
to the total dose and duration of bisphosphonate use. Bisphospho-
nates have been shown to cause fetal developmental abnormalities in
laboratory animals. The uptake of bisphosphonates into fetal bone may
be greater than into maternal bone creating a possible risk for skeletal or
other abnormalities in the fetus. Many drugs, including bisphosphonates,
may be excreted in milk and may be absorbed by nursing animals.
Increased bone fragility has been observed in animals treated with bis-
phosphonates at high doses or for long periods of time. Bisphosphonates
inhibit bone resorption and decrease bone turnover which may lead to
an inability to repair micro damage within the bone. In humans, atypical
femur fractures have been reported in patients on long term bisphospho-
nate therapy; however, a causal relationship has not been established.
ADVERSE REACTIONS: The most common adverse reactions reported
in the ﬁeld study were clinical signs of discomfort or nervousness, colic
and/or pawing. Other signs reported were lip licking, yawning, head
shaking, injection site swelling, and hives/pruritus.
POST-APPROVAL EXPERIENCE (December 2018): The following adverse
events are based on post-approval adverse drug experience reporting.
Not all adverse events are reported to FDA/CVM. It is not always possible
to reliably estimate the adverse event frequency or establish a causal
relationship to product exposure using these data.
The following adverse events are listed in decreasing order of reporting
frequency: renal failure, polyuria, polydipsia, abdominal pain, anorexia,
lethargy, hypercalcemia, behavioral disorder, discomfort, hyperkalemia,
hyperactivity, recumbency, hyperthermia, injection site reactions, muscle
tremor, urticaria, hyperglycemia, and fracture. In some cases, death has
been reported as an outcome of the adverse events listed above.
INFORMATION FOR HORSE OWNERS: Owners should be advised to:
• NOT administer NSAIDs.
• Ensure horses have access to adequate water before and
after administration of OSPHOS.
• Observe their horse for at least 2 hours post-treatment for
signs of colic, agitation, and/or abnormal behavior.
• If a horse appears uncomfortable, nervous, or experiences
cramping post-treatment, hand walk the horse for 15 minutes.
If signs do not resolve contact the veterinarian.
• Monitor water intake and urine output for 3-5 days post-
• Contact their veterinarian if the horse displays abnormal
clinical signs such as changes in drinking and urination,
appetite, and attitude.
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