Comprehensive Vet Guide 2025: Vetoryl® (Trilostane) for Dogs 🐾💊

Written by Dr Duncan Houston, BVSc – trusted veterinarian & Ask A Vet founder 👨‍⚕️🐾

This thorough 2025 guide covers Vetoryl®—brand-name trilostane—our leading treatment for canine Cushing’s disease (hyperadrenocorticism). Learn how it works, dosing, monitoring, side effects, safety tips, and how Ask A Vet, Woopf & Purrz support your dog’s health journey. 🩺📘

1. What Is Vetoryl® & How It Works

Trilostane inhibits 3β-hydroxysteroid dehydrogenase—blocking cortisol (and to a lesser extent aldosterone) production in the adrenal glands, reversing the overproduction seen in Cushing’s disease :contentReference[oaicite:2]{index=2}.

Vetoryl® is FDA-approved for treating both pituitary- and adrenal-dependent Cushing’s in dogs and is considered safer and more predictable than older therapies like mitotane :contentReference[oaicite:3]{index=3}.

2. Who Needs Vetoryl®?

• Dogs with confirmed Cushing’s (pituitary or adrenal origin) via lab tests and clinical signs :contentReference[oaicite:4]{index=4}.
• Dogs showing clinical signs such as polyuria, polydipsia, panting, muscle wasting, pot-belly, excess shedding or recurrent infections :contentReference[oaicite:5]{index=5}.
• Occasionally used off-label for alopecia X, under vet supervision :contentReference[oaicite:6]{index=6}.

3. Dosing & Administration

Start low: **1–3 mg/lb (2.2–6.7 mg/kg) once daily** with food :contentReference[oaicite:7]{index=7}.

Dose adjustments may follow based on follow-up ACTH stimulation testing.

If daily dosing isn't enough, splitting into morning/evening doses is safe—simply divide total daily amount accordingly :contentReference[oaicite:8]{index=8}.

4. Monitoring Your Dog on Vetoryl®

• 10–14 days after starting: repeat ACTH stimulation test 4–6 hrs post-dose + bloodwork (liver, electrolytes, etc.) :contentReference[oaicite:9]{index=9}.
• Monitoring frequency: once dose is stable—rechecks every 1–3 months (exam + labs) :contentReference[oaicite:10]{index=10}.
• Owner watch: hydration, energy, appetite, GI signs—report any concerns.
• Quality of life: standardized owner questionnaires can help track progress :contentReference[oaicite:11]{index=11}.

5. When Does It Start Working?

Trilostane quickly lowers cortisol; clinical improvement often seen within 1–4 weeks—signs like drinking, panting, and skin/coat health begin improving :contentReference[oaicite:12]{index=12}.

6. Possible Side Effects

• Excessively low cortisol → Addisonian crisis: vomiting, diarrhea (especially bloody), lethargy, weakness, collapse—urgent vet care needed :contentReference[oaicite:13]{index=13}.
• Mild GI upset—vomiting or decreased appetite—more common early in treatment :contentReference[oaicite:14]{index=14}.
• Electrolyte imbalances, liver changes—detected via regular labs :contentReference[oaicite:15]{index=15}.

7. Handling & Safety Tips

• Give pills with food to improve absorption
• Wear gloves; avoid contact if pregnant/have cortisol-sensitive conditions :contentReference[oaicite:16]{index=16}.
• If a dose is missed—give when remembered unless near next scheduled dose; don’t double up :contentReference[oaicite:17]{index=17}.

8. Drug Interactions & Precautions

• NSAIDs and corticosteroids: use cautiously—vet may recommend washout periods :contentReference[oaicite:18]{index=18}.
• Ketoconazole and other CYP inhibitors may affect trilostane levels—monitor closely :contentReference[oaicite:19]{index=19}.
• Avoid in dogs with severe liver/kidney disease, or certain cardiac conditions without vet approval :contentReference[oaicite:20]{index=20}.

9. Role of Ask A Vet, Woopf & Purrz

• Ask A Vet: Dosage adjustments, follow-up planning, Addison’s risk advice.
• Woopf: Testing reminders (10–14 day, then each 1–3 months) & medication alerts.
• Purrz: Log energy, drinking, appetite, stool; share trends with your vet.

10. Real-World Insights

Many dogs enjoy reductions in panting, drinking and improved coat health within weeks. Using standardized owner check-ins improves long-term results :contentReference[oaicite:21]{index=21}.

11. FAQs

🐾 Should Vetoryl be split BID?

If once-daily dosing doesn't seem to last all day, splitting dose is safe—divide total appropriately :contentReference[oaicite:22]{index=22}.

🐾 How quickly after starting does monitoring begin?

After 10–14 days, post-pill ACTH test and biochemistry provide a clear readout of hormonal control :contentReference[oaicite:23]{index=23}.

🐾 What if my dog vomits after a dose?

Offer small amount of food and monitor. If repeated vomiting occurs, contact your vet—blood tests may be needed.

🐾 How long will my dog be on Vetoryl?

Usually lifelong, as Cushing’s is managed not cured. Many dogs stay on stable doses for years with regular monitoring.

12. Summary Table

13. Final Thoughts from Dr Duncan

Vetoryl® is a trusted treatment for managing Cushing’s in dogs. Its predictable dosing and monitoring have made it safer than older treatments. With structured testing, owner vigilance, and the support of Ask A Vet, Woopf & Purrz, many dogs thrive while eating, playing, and living more comfortably. Stay engaged with labs, follow health prompts, and partner closely with your vet. 💗🐾

For care guidance, dosing reminders, monitoring support, and expert consultation, visit AskAVet.com and download the Ask A Vet app. Your dog’s wellbeing shines with informed, loving care. 🐶📱