View Osphos Drug Facts Sheet.

Administer 1.8 mg/kg by intramuscular injection up to a maximum dose of 900 mg per horse. Divide the total volume evenly into three separate injection sites. Discard unused vial contents. Osphos is provided in a single use vial and does not contain a preservative.

Clinical improvement is most evident at 2 months post-treatment (see Effectiveness). Of the horses that responded to treatment with Osphos in the field study, 65% maintained their level of improvement through the 6 month evaluation.

If there is no response to initial therapy, the horse should be re-evaluated. For horses that initially respond to Osphos but do not maintain their clinical improvement for 6 months, Osphos may be re-administered at 3 to 6 month intervals based on recurrence of clinical signs. For horses that respond to Osphos and maintain clinical improvement for 6 months, Osphos should be re-administered after clinical signs recur.

Caution:

Federal law (USA) restricts this drug to use by or on the order of a licensed veterinarian.For intramuscular use in horses only.

Contraindications:

Horses with hypersensitivity to clodronate disodium should not receive Osphos.

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 exposure.

Precautions:

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 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.

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. Bisphosphonates 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 bisphosphonates 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 microdamage within the bone. In humans, atypical femur fractures have been reported in patients on long term bisphosphonate therapy; however, a causal relationship has not been established.