🧠 Treatment of Pituitary Cushing’s Syndrome in Dogs – A 2025 Vet’s Guide

By Dr Duncan Houston, BVSc

📌 Does Every Dog with Cushing’s Need Treatment?

Not necessarily. Cushing’s is treated to improve your dog’s quality of life. If symptoms are mild and manageable (e.g. increased thirst but no incontinence or infections), treatment may be postponed. But if your dog has frequent bladder infections, muscle loss, blood pressure issues, or food-stealing behavior, treatment is strongly recommended. 🐾

💊 Primary Medications for Pituitary-Dependent Cushing’s

1. 🧬 Trilostane (Vetoryl®)

Most commonly prescribed treatment today

• 💊 Inhibits the enzyme that helps make cortisol
• 🕐 Given once or twice daily with food
• 📈 Less likely to cause permanent adrenal damage vs. Lysodren®
• 📊 Requires regular ACTH stimulation tests to adjust dosing

Side Effects:

• 😴 Mild lethargy or appetite loss at start
• ⚠️ Rare risk of Addisonian crisis (adrenal shutdown), often unpredictable

✅ Trilostane is approved for dogs, widely available, and often preferred by veterinarians for safety and accessibility.

2. ☢️ Lysodren (Mitotane or o,p’-DDD)

The traditional therapy

• ⚕️ Chemotherapy-like drug that erodes the adrenal gland
• 🕓 Given twice weekly after induction phase
• 📈 Requires frequent ACTH tests for monitoring
• 💊 Effective but riskier in high doses

Induction Phase:

• 💉 Twice daily with meals
• 📊 ACTH test done after 7–9 days or earlier if side effects appear
• 🥣 Appetite reduction may signal endpoint—call your vet

Maintenance Phase:

• 📆 ACTH tests at 1 month, then every 6 months
• 🩺 Watch for signs of over-suppression: appetite loss, vomiting, lethargy

Reversal:

Veterinarians often provide a prednisone “antidote” pill to reverse any sudden drop in cortisol. Most reactions resolve in under 30 minutes. ⏱️

💥 Addisonian Crisis – What to Know

If either trilostane or Lysodren causes excessive cortisol suppression, an Addisonian crisis can occur. This means the body lacks cortisol and cannot respond to stress. Symptoms include:

• 🧃 Vomiting or diarrhea
• ⚖️ Sudden appetite loss
• 😴 Lethargy or collapse

💊 If you suspect this, administer emergency prednisone (if prescribed) and contact your vet immediately. ⚠️

📉 Comparing Trilostane vs. Lysodren

🧴 Alternative Medications (Rarely Used)

🦠 Ketoconazole

• Antifungal drug that suppresses steroid production
• Used when other meds are contraindicated
• ❌ Less effective, not widely used anymore

🧠 Selegiline (Anipryl®)

• Increases dopamine to suppress ACTH
• Only works in specific pituitary cases (rare)
• Breaks down into amphetamines—mild stimulant

🔪 What About Surgery?

The pituitary tumor causing Cushing’s lies at the base of the brain. Surgery is highly complex, requires neurosurgical expertise, and is rarely performed in the U.S. Though more common in Europe, most dogs are managed medically in North America. 🧠

📲 Ask A Vet for Treatment Support

Choosing the right therapy for your dog’s pituitary Cushing’s takes time, knowledge, and close monitoring. Our team can help with medication questions, dose adjustments, and monitoring plans. 🩺

Visit AskAVet.com or open the Ask A Vet App for real-time support and expert care. 🐶📱

✅ Summary: Key Takeaways

• 🧠 Pituitary-dependent Cushing’s is usually treated medically
• 💊 Trilostane is preferred for its safety and approval status
• ☢️ Lysodren is effective but requires careful dosing
• 🧪 ACTH tests are crucial for both drugs
• ⚠️ Watch for Addisonian symptoms (appetite loss, vomiting, lethargy)
• 📆 Maintenance is lifelong—communication with your vet is key

💬 Final Words from Dr Duncan Houston

Managing Cushing’s doesn’t mean managing alone. With guidance, your dog can enjoy months—and often years—of good health, energy, and joy. Whether you’re navigating side effects or choosing between trilostane and Lysodren, your vet team is here to help. 🐕💙

For personalized help, medication reviews, or ACTH scheduling, reach out via the Ask A Vet App or visit AskAVet.com. We’re here to support you and your pet every step of the way. 🐾📱