Vidalta is a sustained-release carbimazole tablet manufactured by MSD Animal Health for the treatment of hyperthyroidism in cats. Hyperthyroidism is the most common hormonal disorder in older cats, affecting up to 10% of cats over age 10. Vidalta's once-daily dosing makes it more convenient than standard carbimazole, which requires twice-daily administration.

Price Comparison

Vidalta tablets (per month supply):

  • From your vet: £25–£45 per month
  • Online pharmacies (with prescription): £15–£28 per month
  • Standard carbimazole (non-sustained release): £8–£18 per month from online pharmacies

Savings of 35–50% are achievable by buying Vidalta online. Standard carbimazole is even cheaper but requires twice-daily dosing, which many cat owners find difficult.

What Does Vidalta Treat?

Vidalta is licensed for the stabilisation of feline hyperthyroidism prior to thyroidectomy and for the long-term treatment of feline hyperthyroidism. The thyroid gland produces excess thyroid hormone, causing weight loss, increased appetite, hyperactivity, vomiting, and heart problems if untreated.

Species and Forms

  • Cats only: Sustained-release coated tablets in 10mg and 15mg sizes
  • Dosing: Typically started at 10mg or 15mg once daily, adjusted based on blood test results
  • Important: Tablets must not be split or crushed as this destroys the sustained-release mechanism

Side Effects

  • Vomiting, diarrhoea, and reduced appetite — most common in the first weeks
  • Facial itching and self-excoriation — a known carbimazole side effect; stop medication and contact your vet immediately
  • Blood disorders (neutropenia, thrombocytopenia) — rare but serious; regular blood monitoring is essential
  • Liver changes — occasional elevations in liver enzymes
  • Regular blood tests (every 3–6 months) are required to monitor thyroid levels, kidneys, and blood cell counts

Prescription Requirements

Vidalta is POM-V. Obtain a written prescription from your vet to buy from online pharmacies at reduced prices.

Alternatives

  • Standard carbimazole: Cheaper but twice daily — £8–£18/month online
  • Thyforon (thiamazole): Twice daily tablets — £10–£20/month online
  • Thyroid diet (Hill's y/d): Iodine-restricted food — sole diet approach, £40–£60/month
  • Radioactive iodine treatment: Curative one-off treatment, £2,000–£3,500 at specialist centres
  • Thyroidectomy: Surgical removal, £1,500–£3,000

How to Save

  • Written prescription: Save 35–50% by buying online
  • Consider standard carbimazole: If your cat accepts twice-daily tablets, it is significantly cheaper
  • Radioactive iodine: A one-off cost of £2,000–£3,500 can be cheaper than years of daily medication
  • Compare prices: Use VetCost to compare pharmacy prices

Last updated: March 2026. Sources: VMD product datasheet, CMA provisional decision (October 2025), VetCost pharmacy data.