Vetoryl Capsules should be administered orally, once daily, with food. In clinical studies, an average starting dose of 6 mg/kg once daily was effective. The dose should then be titrated according to individual response as determined by monitoring (see below). Practical starting doses are recommended as follows:
In clinical studies, most dogs were eventually stabilised on doses between 2-10 mg/kg/day.
Should symptoms not be adequately controlled for an entire 24 hour inter-dose period, consideration should be given to increasing the daily dose by as small an increment as possible and dividing it 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.
Due to the limitation in capsule size, it may not be possible to provide optimal control for smaller dogs requiring lower doses of trilostane.
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.
Regular assessment of the clinical progress of the disease should also be made at each of the above time points.
Dogs should be monitored at regular intervals for primary hepatic disease, renal disease, and for diabetes mellitus. Only complete blister strips should be dispensed. Do not use in dogs weighing less than 20 kg. Do not use in animals suffering from primary hepatic disease and/or renal insufficiency. Do not use in pregnant or lactating bitches or in any animals intended for breeding.
The 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.
Adverse reactions: If you notice any serious effects or other effects not mentioned in the data sheet, please inform your veterinary surgeon. Corticosteroid withdrawal syndrome or hypocortisolaemia should be distinguished from hypoadrenocorticism by evaluation of serum electrolytes.
Signs associated with iatrogenic hypoadrenocorticism, including weakness, lethargy, anorexia, vomiting and diarrhoea may occur, particularly if monitoring is not adequate. Signs are generally reversible within a variable period following withdrawal of treatment. Acute Addisonian crisis (collapse) may also occur. Lethargy, vomiting, diarrhoea and anorexia have been seen in dogs treated with trilostane in the absence of evidence of hypoadrenocorticism.
There have been occasional isolated reports of adrenal necrosis in treated dogs which may result in hypoadrenocorticism. Subclinical renal dysfunction may be unmasked by treatment with the product. Treatment may unmask arthritis due to a reduction in endogenous corticosteroid levels. A small number of reports have been received of sudden death during trilostane treatment. Other mild, rare, adverse effects include ataxia, hypersalivation, bloating, muscle tremors and skin changes.
Special warnings: 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 product is contraindicated in these cases.
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.
Subsequent close monitoring during treatment should be carried out. Particular attention should be paid to liver enzymes, electrolytes, urea and creatinine.
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.
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.
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.
Overdose: Overdose may lead to signs of hypoadrenocorticism (lethargy, anorexia, vomiting, diarrhoea, cardiovascular signs, collapse). There were no mortalities following chronic administration at 3x the maximum recommended dose to healthy dogs, however mortalities may be expected if higher doses are administered to dogs with hyperadrenocorticism. There is no specific antidote for trilostane. Treatment should be withdrawn and supportive therapy, including corticosteroids, correction of electrolyte imbalances and fluid therapy, may be indicated depending on clinical signs. In cases of acute overdosage, induction of emesis followed by administration of activated charcoal may be beneficial. Any iatrogenic adrenocortical insufficiency is usually quickly reversed following cessation of treatment. However in a small percentage of dogs, effects may be prolonged. Symptomatic treatment or appropriate replacement therapy should be initiated. Following a one week withdrawal of trilostane treatment, treatment should be reinstated at a reduced dose rate.
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.
In the event of accidental ingestion, seek medical advice immediately and show the package leaflet or label to the physician. People with known hypersensitivity to trilostane or any of the excipients should avoid contact with the product.
General precautions: For animal treatment only. Keep out of the reach and sight of children. Do not store above 25°C. Keep the blister strips in the carton. Do not use after the expiry date stated on the blister.
Disposal: Dispose of any unused product and empty containers in accordance with guidance from your local waste regulation authority.