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POM-V Prescription Required Companion Animal

Vetoryl 120 mg Hard Capsules for Dogs

Active ingredient: Trilostane

Form

Capsule

Species

Dogs

Manufacturer

Dechra Regulatory B.V.

VMD MA No.

50406/5020

What it's used for

For the treatment of pituitary-dependent and adrenal-dependent hyperadrenocorticism (Cushing’s disease and syndrome).

Full indications, dosage and side effects ↓
View official SPC (PDF)

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  1. 1

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  2. 2

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    The CMA found online pharmacies 50–60% cheaper than practice dispensing on common medicines — typically £200–£300 a year.

Prescription required

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Clinical information

Vetoryl 120 mg Hard Capsules for Dogs — SPC Details

Source: VMD Summary of Product Characteristics (SPC). Last updated 27 Mar 2026.

For the treatment of pituitary-dependent and adrenal-dependent
hyperadrenocorticism (Cushing’s disease and syndrome).
The starting dose for treatment is approximately 2 mg/kg, based on available
combinations of capsule sizes. Administer once daily, with food.
To ensure a correct dosage, body weight should be determined as accurately as
possible.
Titrate the dose according to individual response, as determined by monitoring (see
below). If a dose increase is required, use combinations of capsule sizes to slowly
increase the once daily dose. A wide range of capsule sizes enables optimum dosing for
the individual dog. Administer the lowest dose necessary to control the clinical signs.
Ultimately, if symptoms are not adequately controlled for an entire 24 hour inter-dose
period, consider increasing the total daily dose by up to 50% and dividing it equally
between morning and evening doses.
Do not divide or open capsules.
A small number of animals may require doses significantly in excess of 10 mg per kg
body weight per day. In these situations appropriate additional monitoring should be
implemented.
Monitoring:
Samples should be taken for biochemistry (including electrolytes) and an ACTH
stimulation test pre-treatment and then at 10 days, 4 weeks, 12 weeks, and thereafter
every 3 months, following initial diagnosis and after each dose adjustment. It is
imperative that ACTH stimulation tests are performed 4 – 6 hours post-dosing to enable
accurate interpretation of results. Dosing in the morning is preferable as this will allow
your veterinary surgeon to perform monitoring tests 4-6 hours following administration of
the dose. Regular assessment of the clinical progress of the disease should also be
made at each of the above time points.
In the event of a non-stimulatory ACTH stimulation test during monitoring, treatment
should be stopped for 7 days and then re-started at a lower dose. Repeat the ACTH
stimulation test after a further 14 days. If the result is still non-stimulatory, stop treatment
until clinical signs of hyperadrenocorticism recur. Repeat the ACTH stimulation test one
month after re-starting treatment.
A dose adjustment may be necessary if the dog is swapped from Vetoryl hard capsules
to Vetoryl chewable tablets, or vice versa, as a strict interchangeability between the two
products cannot be assured, as some dogs may respond differently to the change in
pharmaceutical form.
Do not use in animals suffering from primary hepatic disease and/or renal insufficiency.
Do not use in dogs weighing less than 20 kg.
Do not use in cases of hypersensitivity to the active substance or to any of the excipients.

Amended pages: March 2025
Dogs:
Uncommon
(1 to 10 animals / 1,000 animals
treated):
Lethargy
a,b
, Anorexia
a,b
Vomiting
a,b
, Diarrhoea
a,b
Rare
(1 to 10 animals / 10,000
animals treated):
Hypoadrenocorticism
c
Hypersalivation
d
, Bloated
d
,
Ataxia
d
, Muscle tremor
d
Skin disorders
d
Renal insufficiency
e
Arthritis
e
Weakness
a,b
Very rare
(<1 animal / 10,000 animals
treated, including isolated
reports):
Adrenal necrosis
f
Sudden death
a
associated with iatrogenic hypoadrenocorticism, particularly if monitoring is not
adequate (see section 4.9); generally reversible within a variable period following
withdrawal of treatment.
b
has been seen in dogs treated with trilostane in the absence of evidence of
hypoadrenocorticism.
c
including Acute Addisonian Crisis (collapse) (see section 4.10).
d
mild
e
unmasked by treatment with the product due to a reduction in endogenous
corticosteroid levels.
f
may result in hypoadrenocorticism
Corticosteroid withdrawal syndrome or hypocortisolaemia should be distinguished from
hypoadrenocorticism by evaluation of serum electrolytes.
Reporting adverse events is important. It allows continuous safety monitoring of a
veterinary medicinal product. Reports should be sent, preferably via a veterinarian, to
either the marketing authorisation holder or its local representative or the national
competent authority via the national reporting system. See the package leaflet for
respective contact details.
An accurate diagnosis of hyperadrenocorticism is essential.
Where there is no apparent response to treatment, the diagnosis should be re-evaluated.
Dose increases may be necessary.
Veterinarians should be aware that dogs with hyperadrenocorticism are at increased risk
of pancreatitis. This risk may not diminish following treatment with trilostane.

Special precautions for safe use in the target species:
As the majority of cases of hyperadrenocorticism are diagnosed in dogs between the
ages of 10-15 years, other pathological processes are frequently present. It is particularly
important to screen cases for primary hepatic disease and renal insufficiency as the
veterinary medicinal product is contraindicated in these cases.
Subsequent close monitoring during treatment should be carried out. Particular attention
should be paid to liver enzymes, electrolytes, urea and creatinine.
The presence of diabetes mellitus and hyperadrenocorticism together requires specific
monitoring.
If a dog has previously been treated with mitotane, its adrenal function will have been
reduced. Experience in the field suggests that an interval of at least a month should
elapse between cessation of mitotane and the introduction of trilostane. Close monitoring
of adrenal function is advised, as dogs may be more susceptible to the effects of
trilostane.
The veterinary medicinal product should be used with extreme caution in dogs with pre-
existing anaemia as further reductions in packed-cell volume and haemoglobin may
occur. Regular monitoring should be undertaken.
Special precautions to be taken by the person administering the veterinary medicinal
product to animals:
Trilostane may decrease testosterone synthesis and has anti-progesterone properties.
Women who are pregnant or are intending to become pregnant should avoid handling the
capsules.
Wash hands with soap and water following accidental exposure and after use.
The content of the capsules may cause skin and eye irritation and sensitisation. Do not
divide or open capsules: in the event of accidental breakage of the capsules and contact
of the granules with eyes or skin, wash immediately with plenty of water. If irritation
persists, seek medical advice and show the package leaflet/label to the physician
People with known hypersensitivity to trilostane or any of the excipients should avoid
contact with the veterinary medicinal product.
In case of accidental ingestion, seek medical advice immediately and show the package
leaflet or label to the physician.
Special precautions for the protection of the environment:

Amended pages: March 2025
Not applicable.
Other precautions:
Not applicable.
Amended pages: March 2025
The possibility of interactions with other medicinal products has not been specifically
studied. Given that hyperadrenocorticism tends to occur in older dogs, many will be
receiving concurrent medication. In clinical studies, no interactions were observed.
The risk of hyperkalaemia developing should be considered if trilostane is used in
conjunction with potassium-sparing diuretics or ACE inhibitors. The concurrent use of
such drugs should be subject to a risk-benefit analysis by the veterinary surgeon, as
there have been a few reports of deaths (including sudden death) in dogs when treated
concurrently with trilostane and an ACE inhibitor.
Do not store above 25°C. Keep the blister strips in the outer carton.
Not applicable.
4.

This information is sourced from the official Summary of Product Characteristics (SPC) published by the Veterinary Medicines Directorate (VMD). It is provided for informational purposes only and does not replace professional veterinary advice. Always consult your vet before administering any medication.

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