💊 Vet Warning 2025: Right Dorsal Colitis from Phenylbutazone Use in Horses 🐴⚠️

Author: Dr Duncan Houston, BVSc

Phenylbutazone (Bute) is one of the most commonly used non-steroidal anti-inflammatory drugs (NSAIDs) in equine medicine. While effective for pain and inflammation, Bute carries a significant risk—especially if misused or given to horses with other health concerns. One of the most serious side effects is Right Dorsal Colitis (RDC), an inflammatory condition of the colon that can be fatal. In this 2025 update, Dr Duncan Houston explains how RDC develops, how to recognize it early, and how to use NSAIDs more safely. 🐎💉

📍 What Is Right Dorsal Colitis?

Right Dorsal Colitis is a life-threatening inflammation and ulceration of the right dorsal colon in horses. It’s most commonly caused by extended or excessive use of NSAIDs—particularly Bute, though Banamine can also be a culprit. 🔬

What Happens:

• 🔥 NSAIDs reduce protective prostaglandins in the gut
• 💥 Mucosal injury develops in the right dorsal colon
• 💉 Blood and protein leak into the gut
• 🩸 Ulcers or perforations may occur in severe cases

⚠️ Early Signs of Right Dorsal Colitis

• 🔁 Intermittent or severe colic episodes
• 💩 Diarrhea (watery or loose)
• 😴 Depression or lethargy
• 📉 Decreased appetite or sudden weight loss

These symptoms may occur suddenly—even in horses on “normal” NSAID doses. Always monitor horses closely when using NSAIDs. 🩺

👶 Who’s Most at Risk?

Surprisingly, RDC is more common in:

• 🐎 Horses under 15 years old (especially competition horses)
• 🐴 Ponies and foals
• 🐎 Horses on long-term Bute for lameness or joint pain

Dehydration, illness, or pre-existing GI disease greatly increase the risk. Never use Bute in these horses without veterinary supervision. ❌

🩺 Treatment for Right Dorsal Colitis

RDC requires aggressive veterinary care:

• 💧 IV fluid therapy
• 🧪 Plasma transfusions to replenish lost protein
• 🧴 Gastrointestinal protectants (e.g., sucralfate, psyllium, misoprostol)
• 🔪 In severe cases, surgical removal of affected colon (rare and complex)

Even with treatment, mortality rates are high (up to 40%). Prevention is key. 🚨

🧠 Dr Duncan Houston’s Advice

"NSAIDs like Bute are powerful tools—but also powerful risks. Always dose carefully, monitor hydration, and avoid use in sick or stressed horses." 🐴🧬

✅ Safer NSAID Use Tips (2025)

• 📋 Always follow your vet’s dosing instructions—never guess
• 🚱 Don’t use NSAIDs in dehydrated or anorexic horses
• 🕒 Limit treatment to the shortest effective duration
• 💊 Use COX-2 selective NSAIDs like Equioxx® for long-term cases
• 🩺 Schedule follow-up bloodwork and physical exams during long-term treatment

🔚 Final Thoughts: Monitor and Minimize Risk

Right Dorsal Colitis is a serious condition—but one that’s largely preventable. If your horse is on Bute or Banamine, stay vigilant for early signs of GI trouble. Use only under veterinary guidance and never treat NSAIDs like routine supplements. 🐎❤️

Need support for NSAID safety or GI health in your horse? Visit AskAVet.com or download the Ask A Vet app for trusted advice. 📱💊