POM-V Prescription Required Companion Animal

Vidalta 10 mg Prolonged-release Tablets for Cats

Active ingredient: Carbimazole

Form

Tablet

Species

Cats

Manufacturer

Intervet International B.V.

VMD MA No.

06376/5040

What it's used for

Treatment of hyperthyroidism and hyperthyroidism-associated clinical signs in cats. Revised: December 2024 AN: 02169/2024

Full indications, dosage and side effects ↓

View official SPC (PDF)

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Paying less for Carbimazole

1

Ask your vet for a written prescription

They must provide one on request. Under the CMA Order the fee is capped at £21 from 2027.
2

Fill it at a registered online retailer

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

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Prescription required

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Clinical information

Vidalta 10 mg Prolonged-release Tablets for Cats — SPC Details

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

Treatment of hyperthyroidism and hyperthyroidism-associated clinical signs in cats.

Revised: December 2024
AN: 02169/2024

Administration with food enhances bioavailability. The timing of treatment and its
relation to feeding should be kept consistent from day to day.
Do not break or crush the veterinary medicinal product tablets as this will affect the
sustained release property.
The aim of treatment is to maintain total thyroxine concentrations (TT4) in the lower end
of the reference range.
The following dose recommendations during the adjustment and maintenance phases
are suggested.
Dosing adjustment should primarily be based upon a clinical assessment of the
individual cat. Monitoring of TT4, full haematology and liver and kidney parameters is
recommended at each follow up visit (see sections 3.5 and 3.6).
Adjustment phase
The starting dose is a single daily oral administration of one tablet of 15 mg carbimazole
per cat. Consideration could be given to a starting dose of one 10 mg tablet daily where
the TT4 concentration is only mildly increased, e.g. between 50 nmol/L and 100 nmol/L.
With the recommended starting dose of one 15 mg tablet once daily, TT4 may decrease
to within the euthyroid range (TT4<50 nmol/L) shortly after treatment initiation. A dose
adjustment may be required as early as 10 days of treatment.
Dose adjustment should be also performed 3, 5 and 8 weeks after initiation of
treatment, depending on both clinical and hormonal responses to treatment.
Maintenance phase
Follow-up visits every 3 to 6 months are recommended. The dose should be adjusted
individually based on clinical signs and TT4. It is advisable to check TT4 10-14 days
after dose adjustment.
The therapeutic dose ranges between 10 mg (one 10 mg tablet) and 25 mg (one 10 mg
tablet and one 15 mg tablet) once daily.
Some cats require doses of less than 10 mg carbimazole daily. Every other day dosing
with 10 mg or 15 mg of carbimazole may be sufficient to control the disease.
Dose increases should not be made in increments of greater than 5 mg.
Doses above 20 mg have only been trialled in a small number of cats and should be
used with caution.

Do not use in cats suffering from concurrent systemic diseases, such as severe primary
liver disease or diabetes mellitus.
Do not use in cats showing signs of auto-immune diseases and/or altered red or white
blood cell counts, such as anaemia, neutropoenia or lymphopenia.
Do not use in cats with platelet disorders (particularly thrombocytopenia) or
coagulopathies.
Do not use in cats with hypersensitivity to mercaptoimidazoles such as carbimazole or
thiamazole (methimazole) or to any of the excipients.
Please refer to section 3.7.

Cats:
Rare
(1 to 10 animals / 10,000
animals treated):
Tachycardia;
Vomiting, Diarrhoea, Blood in vomit, Oral haemorrhage, Blood in
faeces;
Azotaemia
, Elevated liver enzymes
, Anaemia
, Neutrophilia
,
Thrombocytopenia
, Lymphopenia
, Eosinophilia
;
Ataxia;
Pruritus
, Dermatitis
, Erythema
, Alopecia
;
Weight loss, Lethargy, Decreased appetite, Pyrexia, Polydipsia,
Dehydration;
Very rare
(<1 animal / 10,000
animals treated, including
isolated reports):
Disorientation;
Polyuria, Renal vascular disorder
;
Aggression;
Dyspnoea;
Other abnormal test result
.
Depending on the severity, temporary or permanent discontinuation of treatment may
be required.
Severe cases may require temporary or permanent discontinuation of treatment.
These elevations are usually reversible when treatment is discontinued, although
symptomatic therapy (nutritional and fluid support) may be required.
May occur in particular during the first 4-6 weeks of treatment. Discontinuation of
treatment may be required in case of persistent and marked disorder. In most cases,
the abnormality will resolve spontaneously within 1 month after the treatment has been
discontinued.
Usually mild, adequately controlled by symptomatic therapy and do not require
discontinuation of treatment. However, if more severe clinical signs occur that do not
respond to symptomatic therapy, the dose should be reduced or treatment stopped
following a benefit-risk assessment by the responsible veterinarian.
Treatment of hyperthyroidism may result in a reduction of renal perfusion.
Positive antinuclear antibody (ANA).
In cases of serious adverse reactions, mortality, possibly due to the veterinary medicinal
product, might occur if treatment is not discontinued. In many cases adverse reactions
are reversible on cessation of treatment.
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 the national competent authority via the
national reporting system. See the package leaflet for respective contact details.

Thiamazole (methimazole), the active metabolite of carbimazole, inhibits thyroid
hormone production and therefore cessation of treatment with carbimazole will result in
a rapid (within 48 hours) return to pre-treatment thyroid hormone levels. Chronic
administration is therefore necessary unless surgical or radiation-induced thyroidectomy
is performed.
A small proportion of cats with thyroid adenoma may fail to respond or have a poor
response to treatment.
Thyroid carcinoma is a rare cause of hyperthyroidism in the cat and medical
management alone is not recommended in such cases as it is not curative.

Special precautions for safe use in the target species:
Treatment should be adjusted according to a benefit-risk assessment by the responsible
veterinarian in each individual case.
Treatment of hyperthyroidism may result in a reduction in the glomerular filtration rate.
This can lead to unmasking of pre-existent renal dysfunction. Treatment of
hyperthyroidism may also induce an elevation of liver enzymes or a worsening of pre-
existing hepatic disorders. Renal and liver function should therefore be monitored
before and during treatment
Due to risk of leucopenia or haemolytic anaemia, haematology parameters should be
monitored on a regular basis before and during treatment, preferably at each visit of the
dose adjustment phase and maintenance phase (see section 3.9).
Any animal that suddenly appears unwell during therapy, particularly if they are febrile,
should have a blood sample taken for routine haematology and biochemistry.
Neutropenic animals (neutrophil counts <2.5 x 10
/L) should be treated prophylactically
with bactericidal antibiotics and supportive therapy.
Doses above 20 mg have only been trialled in a small number of cats and should be
used with caution.
Therefore, careful monitoring is recommended and the dose should be adjusted in
individual cases following a benefit-risk assessment by the responsible veterinarian.
Special precautions to be taken by the person administering the veterinary medicinal
product to animals:
Wash hands with soap and water after use and when handling litter used by treated
animals.
Do not handle this veterinary medicinal product if you are allergic to antithyroid
veterinary medicinal products. If allergic symptoms develop, such as a skin rash,
swelling of the face, lips or eyes or difficulty in breathing, seek medical advice
immediately and show the package leaflet or label to the physician.
As carbimazole is a suspected human teratogen, women of child-bearing age should
wear gloves when handling litter or vomit of treated cats.
Pregnant women should wear gloves when handling the veterinary medicinal product.
Do not break or crush tablets.
Do not eat, drink or smoke while handling the tablet or used litter.
In the case of accidental ingestion, seek medical advice immediately and show the
package leaflet or the label to the physician.
Carbimazole, as a prodrug of thiamazole (methimazole), may cause vomiting, epigastric
distress, headache, fever, arthralgia, pruritus and pancytopenia. Treatment is
symptomatic.
Special precautions for the protection of the environment:
Not applicable.

Concomitant treatment with phenobarbital may reduce the clinical efficacy of
carbimazole.
Concomitant use of benzimidazole anthelmintics (fenbendazole or mebendazole) has
been shown to reduce the hepatic oxidation of this therapeutic class and may therefore
induce an increase in circulating levels. Accordingly, co-administration of carbimazole
with a benzimidazole is not recommended.
Thiamazole (methimazole) may display immunomodulating properties. This should be
taken into account when considering vaccination of the cat.

Do not store above 25 °C.
Store in the original container.
Protect from light.
Store in a dry place.
Keep the container tightly closed to protect from moisture.
Do not remove the desiccant.

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.