Tiludronate Disodium
**Tiludronate disodium** (also known as tiludronic acid) is a non-nitrogenous bisphosphonate medication primarily utilized in equine medicine to inhibit bone resorption. It is most notably indicated for the intravenous treatment of **navicular disease** and distal tarsal osteoarthritis (bone spavin) in horses. By regulating bone remodeling and decreasing localized inflammation, it can significantly improve lameness associated with these conditions, particularly when administered early in the disease process. > **Clinical Pearl:** As a non-nitrogenous bisphosphonate, tiludronate is generally considered less potent than newer nitrogen-containing bisphosphonates (like zoledronate), but it has a well-established safety and efficacy profile for equine osteoarticular conditions. In human medicine, an oral formulation is used to treat Paget's disease.
Mechanism: Tiludronate works by inhibiting osteoclastic bone resorption. * **Binding:** The drug has a high affinity for calcium and binds strongly to **hydroxyapatite** crystals in the bone matrix, preferentially at sites of active bone turnover (cancellous bone > cortical bone). * **Cellular Uptake:** During bone resorption, osteoclasts take up the bisphosphonate. * **Intracellular Mechanism:** As a non-nitrogenous bisphosphonate, tiludronate is intracellularly metabolized into a non-hydrolyzable **ATP analogue**. * **Apoptosis:** This toxic ATP analogue accumulates within the osteoclast → disrupts cellular energy metabolism (inhibiting ATP-dependent intracellular enzymes) → induces **osteoclast apoptosis** (programmed cell death). * **Result:** Decreased osteoclast function and lifespan lead to a net reduction in bone resorption and stabilization of bone remodeling.
Dosing by species
- Navicular disease · 0.1 mg/kg tiludronic acid slow IV (over 20-30 seconds per 10 mL given) · IV · once daily · 10 days · Alternate injection sites from day to day.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- Renal dysfunction
- Horses producing milk for human consumption
- Horses less than 3 years old (due to lack of data on growing skeletons)
- Pregnant or lactating mares
Adverse effects
- Colic (reduced appetite, abdominal discomfort, pawing, restlessness)
- Muscle tremor (associated with hypocalcemia)
- Fatigue/lassitude
- Sweating
- Injection site reactions (e.g., phlebitis, especially after repeated injections)
- Salivation
- Tail hypertonia
Drug interactions
- Calcium or Magnesium-containing IV fluids (e.g., LRS, Ringer's, Plasma-Lyte, Normasol) · May complex with tiludronate and reduce its availability; do not mix or administer concurrently.
Monitoring
- Clinical Efficacy (improvement in lameness)
- Serum Calcium levels
- Adverse Effects (particularly within the first 4 hours after dosing, watching for colic or muscle tremors)
Overdose
Limited information is available regarding massive overdose. * **Clinical Signs:** The manufacturer reports that doses of 3X the therapeutic dose in horses caused an increased frequency of adverse effects, particularly **signs of colic** and **muscle tremor**. * **Treatment:** Intravenous **calcium administration** should be considered for signs associated with acute hypocalcemia (e.g., severe muscle fasciculations/tremors). Conventional colic treatments are recommended if gastrointestinal signs persist.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.