Tildren for Navicular Syndrome in Horses: When It Helps and When It Does Not

By Dr Duncan Houston

Palmar foot pain is one of the most frustrating causes of equine lameness because the painful area is hidden inside the hoof capsule.

Years ago, many of these horses were simply labelled as having “navicular disease.” That made the problem sound like one structure, one diagnosis, one treatment. We now know it is more complicated. The back of the horse’s foot includes the navicular bone, navicular bursa, deep digital flexor tendon, collateral sesamoidean ligaments, distal impar ligament, coffin joint region, heel structures, and the hoof capsule itself.

Tildren can be useful in the right horse, but it is not a general heel pain injection. It is a bisphosphonate drug that acts on bone turnover, so it is most logical when navicular bone remodelling or bone pain is part of the diagnosis.

The most important decision is not “should we try Tildren?” It is: what structure is actually causing the palmar foot pain?

Quick Answer

Tildren, or tiludronate disodium, is an FDA-approved bisphosphonate used to control clinical signs associated with navicular syndrome in horses. It is most appropriate when navicular bone-related pathology is part of the problem, not when heel pain is primarily from soft tissue injury such as deep digital flexor tendon damage, navicular bursitis, or ligament injury. It must be given by a veterinarian as a slow intravenous infusion over 90 minutes, and it should not be used casually in horses with kidney disease, horses under 4 years old, pregnant or lactating mares, breeding horses, or horses at higher risk from mineral and electrolyte shifts such as HYPP or cardiac disease. (U.S. Food and Drug Administration)

What Is Palmar Foot Pain?

Palmar foot pain means pain coming from the back half of the front hoof.

Owners often describe these horses as:

• Short-strided in front

• Worse on hard ground

• Worse in circles

• Reluctant to land heel first

• Stumbling or tripping

• Landing toe first

• Sore with hoof testers over the frog or heel

• Improved after palmar digital nerve blocks

• Worse after work on firm or uneven surfaces

Navicular syndrome is one major cause of palmar foot pain, but it is not the only one. Merck Veterinary Manual describes navicular syndrome as a degenerative disease complex that can involve the navicular bone, navicular bursa, collateral sesamoid ligaments, distal impar ligament, or deep digital flexor tendon. It is therefore not just a disease of the navicular bone. (Merck Veterinary Manual)

That distinction is the whole reason Tildren needs careful case selection.

If the horse has navicular bone pain, Tildren may make sense.

If the horse has a deep digital flexor tendon tear, navicular bursal inflammation, coffin joint pain, or heel pain from hoof balance alone, Tildren may not be the treatment that actually solves the problem.

What Is Tildren?

Tildren is the brand name for tiludronate disodium, a bisphosphonate drug approved for use in horses.

Bisphosphonates affect bone turnover. The FDA explains that bisphosphonates inhibit bone resorption by affecting osteoclasts, the cells that break down bone. They bind strongly to calcium and accumulate in bone, where they may be released over months to years. (U.S. Food and Drug Administration)

Tildren is indicated for the control of clinical signs associated with navicular syndrome in horses. The official product information lists the dose as 1 mg/kg given as a slow, even intravenous infusion over 90 minutes, and notes that maximum effect may not occur until 2 months after treatment.

That last point matters.

Tildren is not an instant nerve block. It is not a “make them sound this weekend” drug.

It is a bone remodelling medication used in selected cases where the diagnosis fits.

What Tildren Can Help With

Tildren may be considered when the horse has:

• Palmar foot pain localised to the foot

• Navicular syndrome confirmed or strongly suspected

• Radiographic evidence of navicular bone change

• MRI evidence of navicular bone remodelling, oedema, sclerosis, cyst-like change, or flexor cortex pathology

• Clinical signs that match navicular bone involvement

• A treatment plan that also includes corrective farriery and workload management

The FDA field effectiveness study compared Tildren plus corrective shoeing with vehicle control plus corrective shoeing in horses diagnosed with navicular syndrome. The reported success rate was higher in the Tildren group at 2 months, but the difference was modest. That should remind owners that Tildren is part of a treatment plan, not the whole plan.

In practice, I would think of Tildren as most useful when the painful structure is bone-dominant.

Not every sore heel is a bone-dominant case.

What Tildren Will Not Fix

Tildren is less likely to help when the main issue is:

• Deep digital flexor tendon tear

• Navicular bursa inflammation without meaningful bone pathology

• Collateral sesamoidean ligament injury

• Distal impar ligament injury

• Coffin joint collateral ligament injury

• Hoof abscess

• Laminitis

• Sole bruising

• Thin soles

• Poor hoof balance

• Contracted heels or crushed heels without bone-driven navicular pain

• Pain from shoeing, trimming, or long toes

• Neurological or higher limb lameness mistaken for foot pain

University of Illinois explains this clearly: navicular syndrome involves several structures, but radiographs only show the navicular bone. Soft tissue structures inside the hoof usually require MRI for proper evaluation. It also notes that bisphosphonates work on bone, so a horse with major soft tissue injury may not benefit the same way as a horse with primarily bony change. (Veterinary Medicine at Illinois)

That is the biggest clinical mistake with Tildren: using it because the horse has “heel pain” rather than because the horse has navicular bone-associated pain.

Why Diagnosis Matters Before Tildren

Palmar foot pain is not a single diagnosis.

A proper workup may include:

• Hoof testers

• Lameness exam on straight lines and circles

• Hard and soft surface assessment

• Palmar digital nerve block

• Abaxial sesamoid block or other diagnostic blocks if needed

• Radiographs of the foot

• Farrier and hoof balance assessment

• MRI if radiographs are normal or soft tissue injury is suspected

• Ultrasound where it can assess accessible structures

• Review of shoeing, footing, workload, and history

Merck notes that horses with navicular syndrome often improve after a palmar digital nerve block, but imaging is needed to define the condition. Radiographs can show bony changes, but horses without notable radiographic change may still have soft tissue injuries associated with the navicular apparatus. MRI provides a more comprehensive definition of each case. (Merck Veterinary Manual)

This is why a horse should not be given Tildren simply because it blocks to the foot.

Blocking to the foot tells you where the pain is.

It does not tell you which structure is causing it.

Radiographs vs MRI

Radiographs are usually the first imaging step.

They can show:

• Enlarged synovial fossae or vascular channels

• Medullary sclerosis

• Flexor cortex changes

• Distal border fragments

• Enthesophytes

• Cyst-like lesions

• Coffin bone and hoof balance information

But radiographs cannot properly show the deep digital flexor tendon, navicular bursa, collateral sesamoidean ligaments, or distal impar ligament inside the hoof.

University of Illinois states that MRI is considered the gold standard for diagnosing navicular syndrome because it is the only imaging option that thoroughly evaluates the bony and soft tissue structures inside the hoof capsule. (Veterinary Medicine at Illinois)

So if radiographs show clear navicular bone pathology, Tildren may be part of the conversation.

If radiographs are clean but the horse has persistent palmar foot pain, MRI may be needed before deciding whether Tildren makes sense.

How Is Tildren Given?

Tildren is a prescription veterinary drug and must be administered by or on the order of a licensed veterinarian.

The official label states:

• Dose: 1 mg/kg

• Route: intravenous infusion

• Diluent: sterile 0.9% sodium chloride

• Infusion time: slowly and evenly over 90 minutes

• Maximum effect: may not occur until 2 months after treatment

Tildren should not be mixed with calcium-containing solutions such as Lactated Ringer’s solution because it can form complexes with divalent cations.

This corrects a common misconception: Tildren should not be treated as a quick 30-minute convenience infusion. The label specifically recommends a 90-minute infusion to reduce adverse reaction risk, and field studies showed more adverse reactions when the infusion was given over shorter periods.

Should Banamine or Bute Be Given Before Tildren?

This needs to be handled carefully.

The FDA and label warn that NSAIDs should not be used concurrently with Tildren because the combination may increase the risk of renal toxicity and acute renal failure. The FDA states that no safe window has been determined, and that giving NSAIDs from 48 hours before to 48 hours after bisphosphonate treatment may be especially risky. Renal values such as BUN and creatinine should be monitored where appropriate. (U.S. Food and Drug Administration)

That means routine flunixin premedication is not a harmless safety step.

If a horse develops colic-type signs after Tildren and medication is needed, the label recommends non-NSAID treatment because of the renal risk.

The practical message:

Do not plan Tildren around casual Banamine or bute use. Your vet should review recent NSAID exposure, hydration, kidney function, and safer options for discomfort before treatment.

Side Effects and Risks

Tildren is generally used safely in selected horses, but adverse effects are common enough that owners should be prepared.

The main risks include:

• Transient colic signs

• Agitation or abdominal discomfort

• Changes in intestinal motility

• Increased urination or drinking

• Reduced appetite

• Fever

• Neck soreness or stiffness

• Electrolyte or mineral shifts

• Kidney stress, especially with renal disease, dehydration, NSAIDs, or nephrotoxic drugs

• Hypocalcemia-related concerns in susceptible horses

• Increased risk in HYPP horses or unknown carriers

The FDA reports that around 30% to 45% of horses given Tildren show transient colic signs. These usually occur during the infusion or within 4 hours after treatment, may last around 90 minutes, and may improve with hand-walking. Horses should be observed closely for 4 hours after the infusion. (U.S. Food and Drug Administration)

The label also warns that Tildren can affect calcium, magnesium, and potassium concentrations for several hours. Extra caution is needed in horses with HYPP, hypocalcemia, cardiac disease, or other conditions affected by mineral or electrolyte changes.

Horses That Should Not Receive Tildren Casually

Tildren is not suitable for every horse.

Avoid or use extreme caution in horses with:

• Impaired kidney function

• History of kidney disease

• Dehydration or current systemic illness

• Recent or planned NSAID use

• HYPP or possible Impressive bloodlines

• Hypocalcemia

• Cardiac disease

• Pregnancy

• Lactation

• Breeding mares or stallions

• Horses under 4 years old

• Horses intended for human consumption

• Unclear diagnosis

• Soft tissue-only palmar foot pain

• Active laminitis or acute foot pain that has not been diagnosed

The FDA states that safe use has not been evaluated in horses under 4 years old, breeding horses, pregnant mares, or lactating mares. It also warns that bisphosphonates reduce bone turnover and may affect bone growth and bone health in younger horses. (U.S. Food and Drug Administration)

The official label also states that Tildren should not be used in horses with impaired renal function or a history of renal disease.

HYPP Warning

HYPP deserves its own caution.

Tildren can affect potassium, and the label specifically warns that horses with HYPP may be at increased risk for adverse reactions, including colic signs, hyperkalemic episodes, and death. In one field study, a horse later confirmed to be an HYPP carrier died after receiving Tildren. The label recommends considering HYPP genetic testing in horses with possible or known Impressive bloodlines before administration.

This does not mean every Quarter Horse cannot receive Tildren.

It means HYPP risk should not be ignored.

How Worried Should You Be?

Low Risk

This is more likely when:

• The horse is 4 years or older

• Navicular bone involvement is confirmed

• Kidney values are normal

• The horse is well hydrated

• There has been no recent NSAID use

• The horse is not pregnant, lactating, or intended for breeding

• HYPP risk is absent or tested negative

• Tildren is being used as part of a wider farrier and rehab plan

Action: Tildren may be reasonable if your vet believes the diagnosis fits.

Moderate Risk

This is more likely when:

• Radiographs show mild or unclear navicular bone change

• MRI has not been performed

• The horse has mixed bone and soft tissue signs

• The horse recently received NSAIDs

• The horse has mild dehydration risk

• Kidney values have not been checked

• The horse is a Quarter Horse-related breed with unknown HYPP status

Action: pause and clarify the diagnosis and safety profile before treatment.

High Risk

This is more likely when:

• The horse is under 4 years old

• The horse is pregnant, lactating, or intended for breeding

• Kidney disease is present or suspected

• The horse has HYPP or possible Impressive bloodlines and has not been tested

• The horse has cardiac disease or mineral imbalance

• The horse has active colic, dehydration, or systemic illness

• The pain appears primarily soft tissue-related

Action: Tildren is likely inappropriate or needs a very careful risk-benefit discussion.

Critical Risk

This is more likely when:

• The horse has acute kidney injury

• The horse has severe colic signs

• The horse has active hyperkalemia or HYPP signs

• The horse is systemically unwell

• The horse has severe acute foot pain from an undiagnosed cause

• Tildren was recently given and the horse now has severe colic, weakness, collapse, abnormal heart signs, or reduced urination

Action: call your vet immediately.

When Is This an Emergency?

Tildren is usually part of planned lameness management, not emergency treatment.

Call your vet urgently if your horse has:

• Severe colic signs after treatment

• Persistent or worsening abdominal pain

• Collapse or weakness

• Muscle fasciculations or trembling after treatment

• Abnormal heart rate or rhythm

• Dark urine or markedly reduced urination

• Depression, fever, or not eating

• Severe foot pain

• Non-weight-bearing lameness

• Laminitis signs

• Sudden worsening after an injection or infusion

If a horse develops colic-type signs after Tildren, do not automatically reach for Banamine. The FDA and label warn against concurrent NSAID use because of renal toxicity risk. Contact your vet for appropriate non-NSAID treatment decisions. (U.S. Food and Drug Administration)

What Else Can Cause Palmar Foot Pain?

Before Tildren is chosen, the following should be considered.

Deep Digital Flexor Tendon Injury

A deep digital flexor tendon tear inside the hoof can cause heel pain and may not show on radiographs. MRI is often needed.

Navicular Bursa Pain

Navicular bursitis can produce palmar foot pain and may require different treatment, such as bursal medication or bursoscopy in selected cases.

Collateral Sesamoidean Ligament Injury

These ligaments help support the navicular bone. Injury can mimic classic navicular disease.

Distal Impar Ligament Injury

The impar ligament connects the navicular bone to the coffin bone and can be a significant pain source.

Coffin Joint Pain

Coffin joint arthritis or synovitis can overlap with heel pain and may require joint-directed treatment.

Laminitis

Laminitis can cause foot pain, strong digital pulses, hoof heat, and reluctance to move. It is not a Tildren problem.

Hoof Abscess

Sudden severe foot pain is often an abscess until proven otherwise.

Thin Soles and Bruising

Thin-soled horses may be sore on hard ground and may improve with protection, pads, hoof boots, or farrier changes.

Poor Hoof Balance

Long toes, low heels, contracted heels, sheared heels, or poor breakover can overload the palmar foot. Farriery is often the first treatment, not an optional extra.

Merck lists hoof imbalance, long toes, low heels, poor hoof management, contracted heels, and inappropriate shoeing as important factors in navicular syndrome risk and management. (Merck Veterinary Manual)

What Should You Do Before Considering Tildren?

1. Confirm the Pain Is in the Foot

A palmar digital nerve block can help localise pain to the back of the foot, but it does not identify the exact structure.

2. Get Good Radiographs

Radiographs help evaluate the navicular bone and hoof balance. They also help identify coffin bone changes, sole depth, and other foot problems.

3. Consider MRI if the Diagnosis Is Unclear

If the horse blocks to the foot but radiographs do not explain the lameness, MRI is often the most useful next step. MRI can show whether the main problem is bone, tendon, bursa, ligament, or a combination. (Veterinary Medicine at Illinois)

4. Review Hoof Balance With Your Farrier

Tildren will not fix long toes, crushed heels, poor breakover, or bad loading.

5. Check Kidney Health

Your vet may recommend bloodwork, especially BUN and creatinine, before treatment.

6. Review NSAID Use

Tell your vet about any bute, Banamine, firocoxib, or other NSAIDs used recently. The 48-hour window before and after treatment is especially important. (U.S. Food and Drug Administration)

7. Review HYPP Risk

If the horse has Quarter Horse, Paint, Appaloosa, or Impressive bloodlines, discuss HYPP testing before treatment.

8. Check Competition and Sale Rules

Bisphosphonates can persist in bone for long periods, and rules vary by sport, racing authority, sales organisation, and country. The FDA notes that bisphosphonates bind into bone and may be released over months to years. (U.S. Food and Drug Administration)

What Treatment Should Be Used Alongside Tildren?

Tildren should rarely be the only treatment.

A proper palmar foot pain plan may include:

• Corrective trimming and shoeing

• Shortening breakover

• Heel support where appropriate

• Pads or pour-in support in selected horses

• Hoof balance radiographs

• Rest or workload reduction

• NSAIDs at appropriate times, not concurrently with Tildren

• Coffin joint injection if indicated

• Navicular bursa injection if indicated

• Shockwave in selected cases

• PRP, IRAP, or other biologics for selected soft tissue lesions

• Controlled return to work

• Footing changes

• Long-term monitoring

Merck describes navicular syndrome treatment as palliative and often lifelong, relying on corrective farriery, medication of synovial structures, NSAIDs, bisphosphonates, shockwave, and selected surgical options depending on the structures involved. (Merck Veterinary Manual)

The practical point: Tildren may reduce bone-related pain, but farriery and workload management often decide whether the horse stays comfortable.

Common Mistakes Owners Make

Using Tildren Without a Proper Diagnosis

Heel pain is not enough. You need to know whether the painful structure is bone, soft tissue, bursa, joint, or hoof balance-related.

Expecting Immediate Results

Maximum effect may take up to 2 months. Tildren is not an instant fix.

Premedicating With Banamine

NSAIDs around Tildren can increase renal toxicity risk. This is one of the most important safety corrections. (U.S. Food and Drug Administration)

Ignoring Kidney Function

Tildren should not be used in horses with impaired renal function or renal disease history.

Using It in Young Horses

Tildren is approved for horses 4 years and older, and bisphosphonates may affect bone growth and bone health in young horses. (U.S. Food and Drug Administration)

Treating Soft Tissue Injuries Like Bone Disease

A DDFT tear or navicular bursa problem may need a completely different plan.

Skipping the Farrier Plan

No drug outperforms poor hoof mechanics forever.

Forgetting HYPP Risk

HYPP carriers may be at higher risk for serious adverse reactions, including hyperkalemic episodes.

Prevention and Long-Term Management

You cannot prevent every case of navicular syndrome or palmar foot pain, but you can reduce risk and manage progression.

Practical steps include:

• Keep regular farrier appointments

• Avoid long toes

• Maintain good breakover

• Support the heels appropriately

• Avoid undersized shoes

• Manage contracted or sheared heels early

• Use radiographs for chronic hoof balance problems

• Avoid repetitive concussion on hard ground

• Keep body weight controlled

• Build fitness gradually

• Investigate foot soreness early

• Use MRI when persistent heel pain is not explained by radiographs

• Do not mask pain and continue high-level work without diagnosis

• Match shoeing to the horse, not to another horse’s success story

University of Illinois makes the same point in practical terms: navicular syndrome varies widely between horses, so one shoe, one drug, or one treatment plan will not work for every case. Treatment should be selected based on the structures injured, the horse’s use, and the horse’s conformation. (Veterinary Medicine at Illinois)

Myth vs Reality

Myth	Reality
Tildren treats all heel pain	Tildren is most logical when navicular bone pathology is part of the problem
A palmar digital nerve block means the horse needs Tildren	The block localises pain to the foot, but it does not identify the structure
Radiographs are enough in every case	Radiographs show bone, but MRI is often needed to assess soft tissue inside the hoof
Tildren works immediately	Maximum effect may not occur until 2 months after treatment
Banamine before Tildren prevents problems	NSAIDs around Tildren can increase kidney toxicity risk
Tildren is safe for young horses	Safe use has not been evaluated under 4 years, and bisphosphonates may affect bone growth
One Tildren treatment fixes navicular syndrome	Navicular syndrome is usually chronic and often needs ongoing farriery and management

FAQs About Tildren in Horses

Is Tildren used for navicular disease?

Yes. Tildren is FDA-approved for the control of clinical signs associated with navicular syndrome in horses. It is best considered when navicular bone-related disease is part of the diagnosis. (U.S. Food and Drug Administration)

How is Tildren given to horses?

Tildren is given by a veterinarian as a slow intravenous infusion through a jugular catheter. The labelled dose is 1 mg/kg, infused slowly and evenly over 90 minutes.

How long does Tildren take to work?

Maximum effect may not occur until 2 months after treatment. Owners should not expect immediate soundness in the first few days.

Can Tildren cause colic?

Yes. About 30% to 45% of horses given Tildren may show transient colic signs, usually during the infusion or within 4 hours after treatment. Horses should be monitored closely after infusion. (U.S. Food and Drug Administration)

Can Tildren be used with bute or Banamine?

NSAIDs should not be used concurrently with Tildren because of increased risk of renal toxicity and acute renal failure. The FDA states the 48 hours before to 48 hours after treatment may be especially risky, although no exact safe window has been established. (U.S. Food and Drug Administration)

The Bottom Line

Tildren can be a useful tool for selected horses with navicular syndrome, especially when navicular bone remodelling or bone-associated pain is part of the problem.

But it is not a general treatment for every horse with palmar foot pain.

The safest approach is:

• Localise the lameness properly

• Image the foot properly

• Decide whether bone or soft tissue is the main problem

• Review kidney health and hydration

• Avoid concurrent NSAIDs

• Consider HYPP and electrolyte risks

• Use the correct 90-minute infusion protocol

• Build a farrier and workload plan around the diagnosis

• Give the drug time to work

• Monitor carefully after treatment

The biggest mistake is using Tildren to avoid finding the real diagnosis.

The best results come when the horse has the right diagnosis, the right candidate profile, the right farrier plan, and the right expectations.

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If your horse has chronic heel pain, suspected navicular syndrome, or you are unsure whether Tildren fits the diagnosis, ASK A VET™ can help you organise the lameness history, radiographs, MRI findings, farrier plan, and questions to discuss with your treating veterinarian.