Thyforon for dogs



Active ingredient

Levothyroxine Sodium


Hormone medication

What is Thyforon?

Thyforon is a brand name for a drug with the active ingredient levothyroxine sodium. It is a man-made substitute for thyroid hormones that the healthy body naturally produces. In this way, Thyforon replenishes thyroid hormone levels in dogs with hypothyroidism.

What does Thyforon do?

Thyforon contains levothyroxine sodium, which is a man-made version of natural thyroid hormones. Thyroid hormones help regulate many vital processes in your pet’s body, including metabolism, energy levels and body temperature. Thyroid hormones also help many important organs (e.g. heart, brain) to work properly .

When your dog’s body doesn’t produce enough thyroid hormones on its own, low thyroid hormone levels (hypothyroidism) can occur. This can cause symptoms like fatigue, weight gain, hair loss, vomiting, persistent skin infections and intolerance to cold. Seriously affected dogs can experience life-threatening issues like heart problems and seizures.

Thyforon acts as a replacement for the missing thyroid hormone. By taking Thyforon regularly, your dog’s body receives the appropriate levels of this important hormone. Hypothyroidism cannot be cured; it can only be managed. Therefore, Thyforon needs to be given daily for life.

What are the side effects of Thyforon in dogs?

As Thyforon restores physical activity in dogs, other health issues in your dog (e.g. arthritis, heart problems) may become more obvious. For instance, a more active dog is more likely to run and jump around, which will burden arthritic joints. It might seem like the Thyforon has caused the condition, but it’s actually just ‘unmasked’ the problem.

Side effects of Thyforon can also occur with excessive dosage. These side effects include:

  • Increased thirst and urination: This is usually a temporary side effect, especially during the initial dosage adjustment period. However, if it persists or becomes excessive, consult your vet.
  • Weight loss without loss of appetite: This can occur if the Thyforon dosage is too high. Monitor your dog’s weight and appetite closely, and contact your vet if you notice any significant changes.
  • Hyperactivity and excitability: Similar to weight loss, this can be a sign of overdosing. Observe your dog’s behavior and energy levels, and inform your vet if they seem overly active or restless.
  • Panting and rapid heartbeat: These symptoms can also be linked to an excessive Thyforon dosage. Keep an eye on your dog’s breathing and activity level, and report any abnormalities to your vet.
  • Itchy skin: Less than 1 in 10,000 dogs experience skin irritation or increased scratching due to Thyforon. If you notice any skin-related changes, consult your vet to rule out other causes.

After starting Thyforon, your vet will monitor your dog’s response to treatment with follow-up vet visits and blood tests. During these follow-up visits, your veterinarian will adjust your dog’s Thyforon dosage if needed. The most common side effects are usually mild and temporary, especially with proper dosage monitoring. If you notice any concerning side effects or changes in your dog’s behavior after starting Thyforon, always consult your veterinarian promptly.

How to give Thyforon safely

  1. Follow vet instructions: Always give Thyforon exactly as your vet has prescribed. This includes the right dose and frequency. Never adjust the dose on your own, even if your dog seems to be feeling better or worse. If you aren’t sure of the dose prescribed, please call your vet to confirm.
  2. Give medication consistently: Thyforon can be given with or without food, but consistency is key. Contact your vet if you have missed a dose.
  3. Keep regular veterinary check-ups: Monitor your dog’s response and attend scheduled veterinary appointments. Contact your vet promptly if your dog appears unwell in between scheduled appointments
  4. Check with your vet if giving anything else: Your vet should be aware of other drugs your pet is on, but it’s always worth double-checking in case there’s been a miscommunication somewhere. If your dog is on supplements or non-prescription treatments you should also tell your vet when they prescribe Thyforon, as they may not be suitable to be given together. This includes natural and herbal supplements.
  5. Storage and Handling: Store Thyforon according to the instructions on the label, usually in a cool and dry place. Do not store above 25 °C. Wash hands after use. Make sure it’s out of reach of children and other pets. Pregnant women should handle the product with caution. Divided tablets should be stored carefully and used within 4 days.
  6. Report any accidental overdose to your vet immediately: If you have mistakenly given too much Thyforon, report it to your vet as soon as you realise the error. They may recommend inducing vomiting, giving activated charcoal, and/or monitoring, depending on the severity of the overdose.

Thyforon FAQs

Is Thyforon the same as levothyroxine?

Yes, Thyforon is the same as levothyroxine. Thyforon is a brand name for the active ingredient levothyroxine, marketed by Dechra.

How important is thyroid medication for dogs?

Thyroid medication is important for dogs with abnormal thyroid hormone levels. Thyforon replenishes thyroid hormone levels in hypothyroid dogs. This helps your dog’s body to work properly.

How quickly do dogs respond to thyroid medication?

Improvements usually occur over weeks, so dogs may not respond quickly to thyroid medication. However, Thyforon is effective. Activity levels usually improve after 2 weeks. Skin issues usually improve within 1 to 4 months (although hair loss and itchiness will increase at the beginning). All signs of hypothyroidism will usually resolve after 13 weeks of treatment. However, as Thyforon is long-term medication, do not stop it or change the dose without consulting your vet.

Will thyroid medicine help dogs lose weight?

Thyroid medicine will help hypothyroid dogs to lose weight. However, thyroid medicine should not be given to dogs without thyroid problems. Your vet is the best person to determine the cause of obesity in your dog.

Alternatives to Thyforon in dogs

If your dog has hypothyroidism, treatment will help them get back to normal. Thyforon tablets are flavoured, but if your dog doesn’t like taking them then your vet may be able to prescribe another levothyroxine product like:

  • Thyroxanil (non-flavoured tablets)
  • Soloxine (non-flavoured tablets)
  • Leventa (liquid oral solution)

Thyforon Datasheet

All drugs have a manufacturer’s datasheet, which gives information about the drug’s use and possible side effects. There is usually one in your Thyforon box, but if you have lost it you can click on the button below to be taken on an online version.

Courses related to Thyforon

We don’t currently have a course about hypothyroidism in dogs, but you can browse our available courses to see if anything is of interest!