Underactive Thyroid Medication for Dogs

Underactive thyroid medication is necessary when the dog is diagnosed with hypothyroidism. This condition will manifest through lethargy and weight gain. The administration of thyroid medication is recommended and can fix the problem. It’s important to keep an eye on the dog’s thyroid levels to prevent hyperthyroidism.

Symptoms of Underactive Thyroid Glands

The thyroid glands produce the thyroid hormones, which perform numerous tasks, the most important being the role of regulating the metabolism.

When the thyroid glands fail to produce sufficient quantities of thyroid hormones, the dog will gain weight (without actually eating more) and may present additional symptoms such as:

  • Lethargy
  • Lack of interest in activities
  • Hair loss
  • Dry skin and flakiness

The dog requires blood tests, which can confirm if there are low levels of thyroid hormones. The normal levels of thyroid hormones will depend on the dog’s breed and age and are established by the vet. However, if the dog displays symptoms of hypothyroidism, treatment is required.

Underactive Thyroid Medication

The medication treatment that is prescribed to dogs with underactive thyroid glands consists of thyroxine. This substance may be administered in the form of pills or in the form of subcutaneous injections. Thyroxine is an artificial hormone that will compensate for the lack of natural thyroid hormones.

The frequency and dose will be established by the vet and will greatly depend on the dog’s blood tests and his symptoms. A dog that has very low levels of thyroid hormones should get a higher dose of artificial hormones.

However, the dog will have to get blood tests every 2 to 3 weeks, which will monitor the levels of thyroid hormones to establish if the dog needs a lower dose. A maintenance dose will be recommended for a longer period of time and in some cases, it will have to be administered for life. However, in the best case scenario, the dog will start to produce a balanced amount of thyroid hormones and the medication can be discontinued.

Additional treatment may be required to normalize the production of thyroid hormones (i.e. surgery if there is a growth affecting the thyroid glands).

Thyroid Medication Effectiveness

The thyroid medication will start being effective 2 to 4 weeks after the treatment is started. However, the skin and coat will show signs of improvement only after 3 to 4 months of medication treatment.

Side Effects of Thyroid Medication

The administration of thyroxine should reduce the symptoms of hypothyroidism and improve the dog’s metabolism and skin condition, but there may also be some adverse reactions such as:

  • Excessive thirst
  • Increased frequency of urination
  • Agitation
  • Dormant thyroid glands, as they can get used to not having to produce the hormones and will not secret other hormones anymore

If the dose of thyroxine is too high, the dog may display symptoms of hyperthyroidism (i.e. weight loss, agitation, polyuria and polydipsia). These symptoms shouldn’t be ignored and the dose should be lowered immediately.