Trilostane for Dogs: Medication & Safety Guide

Schedule 4 (Prescription Only): Trilostane is a prescription medication registered by the APVMA for use in dogs in Australia.

It is most commonly found under the brand name Vetoryl. It is specifically indicated for the treatment of pituitary-dependent and adrenal-dependent hyperadrenocorticism Cushingʼs Syndrome) in dogs. This medication must only be used under the direct supervision and prescription of a registered veterinarian.

For detailed technical data, you can view the official Product Information (PI) via the APVMA PubCRIS database.

Trilostane is a prescription medication used to treat dogs with Cushingʼs Syndrome (hyperadrenocorticism). This condition occurs when the adrenal glands produce too much cortisol, leading to symptoms like excessive thirst, increased urination, hair loss, and a "pot-bellied" appearance. Trilostane helps manage these symptoms by bringing cortisol levels back into a healthy range, significantly improving a dog's quality of life.

Trilostane is an adrenal steroid synthesis inhibitor. It works by blocking a specific enzyme 3-beta hydroxysteroid dehydrogenase) in the adrenal cortex. By inhibiting this enzyme, the medication effectively reduces the production of cortisol. It does not cure the underlying cause of the condition but controls the excess hormone production that causes the physical symptoms.

Capsules: Available in several strengths (e.g., 5 mg, 10 mg, 30 mg, 60 mg, and 120 mg) to allow for precise dosing based on your dog's size and blood test results.

Dosing Note: Trilostane must be administered with food to ensure it is absorbed properly. It is usually given once daily in the morning, as determined by their veterinarian.

Safety Parity Notice: Because Trilostane alters hormone levels, it is vital to monitor your dog closely, especially during the first few weeks of treatment:

• Digestive Issues: Mild vomiting, diarrhoea, or a temporary loss of appetite.
• Lethargy: Your dog may appear unusually tired or weak. 
• Addisonian Crisis: If cortisol levels drop too low, a serious condition called "Hypoadrenocorticism" can occur. Signs include severe vomiting, shaking, collapse, or extreme weakness. If these occur, contact your vet immediately.
• Behaviour: Some dogs may experience changes in drinking or eating habits as their hormone levels adjust.

This medication should not be used in the following circumstances:

• Liver or Kidney Disease: Not for use in dogs with primary liver disease or severe renal insufficiency.
• Pregnancy: Not for use in pregnant or lactating dogs, or those intended for breeding.
• Known Allergy: Do not use if your dog has a known hypersensitivity toTrilostane.

The following conditions require careful consideration and monitoring by your vet:

• ACTH Stimulation Tests: Regular blood tests (typically performed 46 hours after the morning dose) are essential to ensure the dose is correct and that cortisol levels aren't becoming too low.
• Drug Interactions & Heart Medication: Inform your vet about all other medications. Use extreme caution with ACE inhibitors or potassium-sparing diuretics (like spironolactone), as concurrent use carries a risk of hyperkalaemia, with rare reports of sudden death.
• Pre-existing Conditions: Use with caution in dogs with diabetes mellitus (requires specific monitoring) or anaemia, as further reductions in red blood cells may occur.
• Weight Restriction: The safety of standard capsule sizes 20 mg has not been studied in dogs weighing less than 3 kg.
• Unmasking Other Conditions: A reduction in cortisol may "unmask" underlying issues like arthritis or skin conditions (dermatoses). Your vet may suggest non-NSAID therapies for arthritis to protect kidney function while on Trilostane.
• Handling & Safety: Do not open or break the capsules. Pregnant women or those trying to conceive should handle the medication with extreme care or wear gloves. Always wash hands after handling.

Temperature: Store at room temperature (below 25°C.

Security: Keep the medication in its original blister pack until use. Store it out of reach of children and other animals.

How soon will I see an improvement in my dog?
Symptoms like excessive drinking and eating often begin to improve within the first 2 weeks. Improvements in the skin and hair coat usually take longer, often 3 to 6 months.

Why does my dog need so many blood tests?
Cushingʼs Syndrome is a delicate condition to manage. Regular blood tests (like the ACTH stim test) are the only way to ensure the dose is effectively controlling the cortisol without accidentally dropping it too low, which can be dangerous.

Can I give the capsule without food if my dog isn't hungry?
No. Trilostane requires food in the stomach to be absorbed into the bloodstream.

If your dog refuses to eat, skip the dose and contact your veterinarian for advice.

Will my dog have to take this forever?
Yes. In most cases, Cushingʼs Syndrome is a lifelong condition. Trilostane manages the symptoms but does not "cure" the adrenal or pituitary issue, so daily medication is required to keep your dog comfortable.

What should I do if my dog seems very weak or starts shivering?
Stop the medication immediately and contact your veterinarian. These can be signs that cortisol levels have dropped too low (an Addisonian-like state), which requires prompt veterinary attention

If your veterinarian has determined that Trilostane is appropriate for your pet and has issued a valid Australian prescription, you can fulfil it through our pharmacy service.

Learn more about VLP Pharmacy and the prescription ordering process for medications like Trilostane.

Disclaimer: This information is for educational purposes only and does not replace professional veterinary advice. Always consult your veterinarian before starting any new medication for your pet.