Thyroid pills are given to dogs when their thyroid is either overactive or underactive. Dogs are considered hypothyroid when their thyroid does not produce enough thyroid hormone to support the needs of the dog’s body. Likewise, dogs are considered hyperthyroid when their thyroid produces an excessive amount of thyroid hormone. Because both of these conditions are abnormal to a dog’s needs, they can both be treated with prescription thyroid pills.
Hyperthyroid vs. Hypothyroid
Before a thyroid prescription can be written for your dog, a veterinarian first has to complete a thyroid panel blood test. This allows the veterinarian to examine the exact levels of T3 and T4 within the dog’s body, which helps to determine whether the dog’s thyroid levels are normal, too high or too low and which prescription dose may be most appropriate.
In general, normal thyroid levels in dogs include the following ranges:
- T3 (45 - 150)
- Free T3 (3.0 - 8.0)
- T4 (1.0 - 4.0)
- Free T4 (.65 - 3.0)
Interestingly, the higher the lab value, the more hypothyroid the dog is. As an example, a T4 lab value of 5.0 would be considered hypothyroid, while a T4 value of 1.0 would be considered hyperthyroid. In general, thyroid panel testing is done every 2 to 4 weeks until the dosage that best controls the condition is found. Also, because the thyroid gland is not capable of repairing itself, most dogs will need to be on life-long thyroid hormone replacement therapy.
Hypothyroid Thyroid Pills
Thyroid pills for dogs can be purchased through a veterinarian or online, but it is important to determine the exact amount of medication that will be needed before purchasing any type of thyroid medication. Dogs with hypothyroidism may be prescribed one of these medications:
- Soloxine – Given in dosages of 0.1 mg, 0.2 mg, 0.3 mg, 0.4 mg, 0.5 mg, 0.6 mg, 0.7 mg, 0.8 mg and 1.0 mg per pill. Soloxine is a synthetic form of levothyroxine and is a brand name medication. It may interact with insulin and diabetes medications, so it is important to consider that effect before using this type of thyroid pill.
- Thyro Leventa Oral Suspension – Given in dosages of 1.0 mg/dL. This type of thyroid medication is a liquid suspension form of levothyroxine. However, there is not a generic available for the liquid suspension format.
- L-Thyroxine – This is the generic pill form of synthetic thyroid hormone. It is available in 0.1 mg, 0.2 mg, 0.3 mg, 0.4 mg, 0.5 mg, 0.6 mg, 0.7 mg and 0.8 mg.
Hyperthyroid Thyroid Pills
If your dog’s thyroid produces an excessive amount of thyroid hormone, he will need to be placed on thyroid pill which can help suppress the amount of thyroid hormone produced.
- Methimazole – This is a generic medication given in 5 mg and 10 mg doses. However, the taste of this thyroid pill is known to be very bitter, so it is best to hide it in a treat for easier administration. Methimazole is also available in compounded gel and compounded liquid forms.