Treatment Options for Pituitary Cushing’s Syndrome in Dogs 🐶🧠✨

By Dr Duncan Houston

🔎 Quick Answer

Pituitary-dependent Cushing’s syndrome in dogs is caused by a tumor in the pituitary gland that leads to excess cortisol production. The most common treatment is trilostane, which safely reduces cortisol levels. Mitotane (Lysodren) is an alternative but carries higher risk. Treatment aims to control symptoms and improve quality of life, with regular monitoring being essential to avoid complications such as Addisonian crises.

A diagnosis of Cushing’s can feel like a lot.

Increased drinking.
Constant hunger.
Skin changes.
Infections that keep coming back.

But the important thing to know is this:

👉 Many dogs with Cushing’s can do very well with the right treatment.

🧠 What Is Pituitary Cushing’s Syndrome?

Pituitary-dependent Cushing’s is the most common form of Cushing’s in dogs.

It is caused by:

• a tumor in the pituitary gland

• excessive ACTH production

• overstimulation of the adrenal glands

• excess cortisol release

👉 Cortisol is useful in normal amounts.
👉 Too much causes widespread effects throughout the body.

📌 When Is Treatment Needed?

Not every dog needs treatment immediately.

Treatment is usually recommended when symptoms start to affect:

• quality of life

• comfort

• daily function

• household management

Common reasons to treat include:

• excessive drinking and urination

• accidents in the house

• recurrent skin or urinary infections

• high blood pressure

• muscle loss or weakness

• excessive appetite

👉 The goal is not to “cure” the disease, but to control it.

💊 Main Treatment Options

🏆 Trilostane (Vetoryl®)

This is the most commonly used treatment today.

How it works

• blocks an enzyme involved in cortisol production

• reduces cortisol levels in a controlled, reversible way

Benefits

• widely used and well studied

• reversible effect

• safer profile compared to older treatments

• flexible dosing

Considerations

• requires regular monitoring

• dosing may need adjustment over time

Possible side effects

• lethargy

• reduced appetite

• vomiting or diarrhea

Serious risk: Addisonian reaction

If cortisol drops too low:

• weakness

• vomiting

• collapse

👉 This is why monitoring is essential.

⚖️ Mitotane (Lysodren®)

An older but still used treatment.

How it works

• selectively destroys parts of the adrenal gland

• permanently reduces cortisol production

Treatment phases

• induction phase to control cortisol

• maintenance phase to keep levels stable

Pros

• can be effective

• less frequent dosing long term

• often lower cost

Cons

• higher risk of over-treatment

• irreversible adrenal damage

• requires very careful monitoring

👉 Mitotane is effective but less forgiving than trilostane.

🚨 Addisonian Reactions: What to Watch For

Both trilostane and mitotane can lower cortisol too much.

Signs include:

• vomiting

• diarrhea

• lethargy

• weakness

• collapse

👉 This is a medical emergency.

Early treatment usually leads to good recovery, but delays can be serious.

📉 Less Common Options

Ketoconazole

• antifungal with cortisol-suppressing effects

• inconsistent results

• not commonly used now

Selegiline (Anipryl®)

• affects dopamine and ACTH release

• variable response

• rarely used in modern practice

👉 These are not first-line treatments.

🧠 What About Surgery?

In theory, removing the pituitary tumor would treat the disease.

In practice:

• requires specialised neurosurgery

• limited availability

• higher cost and complexity

👉 Not commonly performed in most regions.

🧠 Medical Adrenalectomy Concept

Some approaches aim to intentionally suppress adrenal function to simplify long-term control.

This is not common in most practices and requires very careful management.

🩺 Monitoring Is Critical

Regardless of treatment choice, monitoring is essential.

This may include:

• ACTH stimulation tests

• bloodwork

• electrolyte checks

• clinical symptom tracking

Monitoring is typically:

• frequent at the start

• then spaced out once stable

👉 Treatment without monitoring is not safe.

🧠 Choosing the Right Treatment

There is no single “perfect” option.

Factors include:

• severity of symptoms

• cost

• ability to monitor regularly

• owner preference

• overall health of the dog

General approach in 2025

• trilostane = first-line in most cases

• mitotane = alternative in selected cases

• other options = rare or case-specific

🐾 Practical Takeaways

• pituitary Cushing’s is manageable, not curable

• trilostane is the most common treatment

• mitotane is effective but higher risk

• monitoring is essential

• over-treatment can be dangerous

• early recognition of side effects matters

💬 Final Thoughts

Cushing’s is a chronic condition.

But it is one we can often manage very successfully.

With the right plan, many dogs:

• feel better

• have improved energy

• have fewer infections

• live good quality lives

The key is not just starting treatment.

👉 It is adjusting, monitoring, and staying consistent over time.

❓ FAQ

What is the best treatment for Cushing’s in dogs?
Trilostane is most commonly used due to its safety and reversibility.

Is Cushing’s curable?
Not usually in pituitary cases, but it can be well managed.

How long can dogs live with Cushing’s?
Many dogs live for years with proper treatment and monitoring.

What is an Addisonian crisis?
A dangerous drop in cortisol caused by over-treatment, requiring urgent care.

Do all dogs need treatment?
No. Mild cases may be monitored, but most symptomatic dogs benefit from treatment.

If you’re unsure whether your dog’s symptoms need treatment or how to manage Cushing’s safely, the ASK A VET™ app can help you track changes and get guidance early.