If your horse has arthritis, navicular, or any chronic pain condition, you've probably used bute. It's cheap, it's effective, and every horse owner knows it.

But vets are increasingly cautious about long-term bute use. The side effects are well-documented: gastric ulcers, right dorsal colitis, kidney damage. For horses needing daily pain management for months or years, these risks add up.

Palmitoylethanolamide (PEA) is gaining attention as an alternative. It's a compound horses produce naturally in their own bodies. It works through different pathways than bute and doesn't carry the same organ risks.

This article breaks down the differences so you can have an informed conversation with your vet.

How Bute Works

Phenylbutazone (bute) is a non-steroidal anti-inflammatory drug (NSAID). It blocks cyclooxygenase enzymes, called COX-1 and COX-2.

COX-2 produces prostaglandins that cause inflammation and pain. Block COX-2, reduce inflammation. That's the therapeutic effect.

COX-1 produces prostaglandins that protect the stomach lining, maintain blood flow to the kidneys, and support the gut mucosa. When bute blocks COX-1, problems start.

Bute is less selective than newer NSAIDs. It hits both COX-1 and COX-2 hard. This makes it effective but also explains its side effect profile.

Other Equine NSAIDs

Bute isn't the only option. Other equine NSAIDs include:

Firocoxib (Equioxx) is more COX-2 selective and causes fewer GI problems than bute. But it costs significantly more, and it still carries some risk with long-term use.

The Risks of Long-Term Bute Use

For a few days of use, bute is generally safe. The problems emerge with weeks, months, or years of daily dosing.

Gastric Ulcers

This is the big one. Studies show that 60-90% of performance horses already have gastric ulcers. Bute makes them worse.

Bute reduces the prostaglandins that protect the stomach lining. The result: increased acid damage and ulcer formation. Horses on long-term bute often need concurrent ulcer treatment with omeprazole, adding cost and complexity.

Right Dorsal Colitis

This is the one that keeps vets up at night. Right dorsal colitis is ulceration and inflammation of the large colon. It can be difficult to diagnose, difficult to treat, and sometimes fatal.

Bute is the most common cause. The condition can develop even at normal doses if given long enough. Early signs: weight loss, low protein levels, intermittent colic, diarrhoea. By the time it's diagnosed, significant damage may already be done.

Kidney Damage

Prostaglandins help maintain blood flow to the kidneys. Bute reduces prostaglandin production. Over time, this can impair kidney function, especially in older horses or those with pre-existing kidney issues.

Dehydration increases the risk. A horse on bute who doesn't drink enough is at higher risk for kidney problems.

Impaired Healing

Prostaglandins play a role in bone and soft tissue repair. Long-term NSAID use can slow healing. This is a concern for horses recovering from tendon injuries, fractures, or surgery.

How PEA Works Differently

PEA (Palmitoylethanolamide) doesn't touch COX enzymes. It works through completely different pathways.

PPAR-α Activation

PEA activates nuclear receptors called PPAR-α. When activated, these receptors reduce the production of inflammatory cytokines. The result is less inflammation without interfering with the prostaglandins that protect the gut and kidneys.

Mast Cell Stabilisation

PEA stabilises mast cells, reducing the release of histamine and other inflammatory mediators. This mechanism is relevant for horses with joint inflammation, soft tissue injuries, and chronic musculoskeletal conditions.

Glial Cell Modulation

Chronic pain often involves changes in the nervous system. Glial cells in the spinal cord become activated and amplify pain signals. PEA helps regulate these cells, which is why it shows promise for chronic pain conditions that don't respond well to NSAIDs.

PEA vs Bute: Side-by-Side Comparison

When to Use Each Option

Bute Makes Sense For:

• Acute injuries requiring rapid pain relief
• Post-surgical pain (short term)
• Severe arthritis flare-ups
• Acute laminitis (with vet supervision)
• Short-term use measured in days, not weeks

PEA Makes Sense For:

• Chronic arthritis requiring ongoing management
• Horses with history of gastric ulcers
• Older horses with declining organ function
• Navicular syndrome
• Back pain and soft tissue injuries
• Long-term use measured in months or years
• Competition horses (no withdrawal period)

Using Both Together

Many vets now use PEA and bute together. The approach: PEA provides daily baseline support while bute is reserved for flare-ups when fast relief is needed.

This combination works because the two compounds act on different pathways. There's no interaction between them. Over time, many horses can reduce or eliminate bute use while maintaining comfort on PEA alone.

A typical protocol: start PEA at full dose alongside existing bute. Maintain both for 4-6 weeks while PEA builds up. Gradually reduce bute dose while monitoring comfort. Some horses come off bute entirely. Others do best on occasional bute with daily PEA.

Competition Considerations

This is where PEA has a clear advantage.

Bute: Controlled substance under FEI and most racing authorities. Detection times vary, but typical withdrawal periods are 7+ days. Getting it wrong means disqualification, fines, or suspension.

PEA: Not currently listed as a prohibited substance by the FEI, Racing Australia, or most national federations. Horses produce it naturally, so there's no detection issue.

For competition horses who need ongoing pain support, PEA allows continuous use right through competition season. No withdrawal calculations, no timing stress.

What About Cost?

Bute is cheap. A month's supply for a 500kg horse costs roughly $20-40 AUD.

PEA costs more. Quality micronized PEA for horses runs $80-150 AUD per month depending on dose and product.

But factor in the hidden costs of long-term bute:

• Omeprazole for gastric ulcer prevention/treatment ($100-300/month)
• Veterinary monitoring
• Blood work to check kidney function
• Treatment costs if right dorsal colitis develops (thousands)

For horses needing long-term pain management, PEA often works out similar or cheaper when you account for the full picture.

How to Transition from Bute to PEA

Don't stop bute suddenly. PEA takes 2-4 weeks to reach full effect. Stopping bute immediately creates a pain gap.

A sensible transition protocol:

Weeks 1-2: Start PEA at full dose (loading dose, higher end of range). Continue existing bute dose unchanged.

Weeks 3-4: Continue both. Watch for improvements in comfort, movement, willingness to work.

Weeks 5-6: If horse is doing well, reduce bute by 25-50%. Continue full PEA dose.

Weeks 7-8: Assess and adjust. Options: further reduce bute, maintain current levels, or discontinue bute entirely.

Work with your vet throughout this process. Every horse responds differently. Some come off bute completely. Others do best on a low bute dose plus PEA. The goal is finding the minimum effective NSAID dose for your horse.

The Bottom Line

Bute works fast and works well. For acute pain and short-term use, it's hard to beat. But it wasn't designed for years of daily dosing, and the risks accumulate.

PEA is slower to act but carries no documented organ risks. For horses needing ongoing pain management, it's a genuine option worth considering.

The choice isn't necessarily either/or. Many horses do best with PEA for daily support and bute reserved for flare-ups. This reduces total NSAID exposure while maintaining quality of life.

Talk to your vet about what makes sense for your horse. And if you want to understand PEA in more depth, read our complete guide to PEA for horses.