Vidalta for Cats
Hyperthyroidism Treatment
Once-daily sustained-release carbimazole for overactive thyroid. A lifelong medication — save up to 50% buying online with a prescription.
Buy Vidalta at UK pharmacy prices
UK registered pharmacies dispense the same Vidalta your vet prescribes, often for less. Ask your vet for a written prescription (capped at £21 under the CMA Order, from 2027), then fill it online.
Affiliate link to The Pharm Pet Co., a UK registered veterinary pharmacy. We may earn a small commission, at no extra cost to you. Always follow your vet's guidance on medication choice and dosing.
What is Vidalta?
Vidalta is a sustained-release tablet containing carbimazole, manufactured by MSD Animal Health. It is used to manage feline hyperthyroidism — a condition where the thyroid gland produces too much thyroid hormone, causing weight loss, increased appetite, hyperactivity, vomiting and heart problems.
Hyperthyroidism is the most common hormonal disorder in cats, affecting approximately 10% of cats over 10 years old. Vidalta works by blocking the enzyme thyroid peroxidase, which is essential for producing thyroid hormones (T3 and T4). By reducing thyroid hormone production, it controls the symptoms and prevents damage to the heart and other organs.
The key advantage of Vidalta over Felimazole is its once-daily dosing. The sustained-release formulation means carbimazole is released slowly throughout the day, maintaining stable blood levels with a single tablet. This is a significant benefit for cats (and owners) who struggle with twice-daily medication.
Sustained-release — half the tablets vs Felimazole
Daily medication needed for life unless cured with radioiodine
Regular T4 and kidney monitoring essential
Vidalta Dosage for Cats
Starting Dose
10 mg or 15 mg once daily, depending on the severity of hyperthyroidism. Available as 10 mg and 15 mg coated tablets. Do NOT crush or break the tablets — this destroys the sustained-release mechanism.
Dose Adjustment
After 3 weeks, blood tests (T4 level) determine whether the dose needs adjusting. The target is a normal T4 range. Dose may be increased to 15 mg or 25 mg if T4 remains high, or reduced if T4 drops too low.
Monitoring Schedule
Blood tests at 3 weeks, 6 weeks, 10 weeks, then every 3-6 months for life. Monitor T4, kidney values (urea, creatinine), liver enzymes and full blood count. Controlling the thyroid can unmask hidden kidney disease.
Side Effects & Warnings
Common Side Effects
- • Vomiting (most common, usually settles)
- • Reduced appetite
- • Lethargy
- • Mild skin irritation (self-resolving)
Serious Side Effects (Rare)
- • Bone marrow suppression (low white cells)
- • Liver damage (monitor enzymes)
- • Facial excoriation (scratching the face)
- • Bleeding disorders (thrombocytopenia)
Vidalta Price Comparison
Vidalta 10 mg — 30 tablets
Vidalta 15 mg — 30 tablets
Vidalta 10 mg — 100 tablets
Vidalta 15 mg — 100 tablets
Lifelong savings: A cat on Vidalta 15 mg daily costs £360-£576/year at the vet vs £192-£336 online. With a £21 prescription, you save £150-£225+ per year. Over a typical 3-5 year treatment period, that is £450-£1,125 in total savings.
Alternatives to Vidalta
Felimazole (Methimazole)
Given twice daily. Same mechanism of action (carbimazole converts to methimazole in the body). May be better for cats needing very precise dose adjustments. See our Felimazole guide.
Radioiodine Treatment (I-131)
A single injection that cures hyperthyroidism permanently. Costs £2,000-£3,000 one-off but eliminates the need for lifelong daily medication. Success rate over 95%. Requires 2-4 weeks hospitalisation at a specialist centre.
Hill's y/d Thyroid Care Diet
A prescription diet with restricted iodine that controls thyroid levels without medication. Must be the ONLY food the cat eats. Around £30-£40/month. Less effective than medication but avoids tablets entirely.
Frequently Asked Questions
Vidalta treats feline hyperthyroidism (overactive thyroid). It is a once-daily sustained-release carbimazole tablet.
£25-£48 for 30 tablets at the vet, £14-£28 online. Annual savings of £150-£225+ buying online.
Vidalta is once daily (carbimazole). Felimazole is twice daily (methimazole). Both are effective. Vidalta is easier to manage.
T4 and kidney function at 3, 6 and 10 weeks, then every 3-6 months. Regular monitoring is essential.
No. Only radioiodine (I-131) or surgery can cure it. Vidalta is lifelong management.
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Save on Vidalta for your cat
Lifelong thyroid medication adds up. Buying online saves £150-£225+ per year.