Hypothyroidism is the deficiency of thyroid hormone and is the most common hormone imbalance of dogs. For various reasons the thyroid can no longer make enough thyroid hormone and we must then supply it.
Thyroid hormone serves as a sort of volume dial for metabolism. Since virtually every cell in the body can be affected by thyroid hormone, it is not surprising that reduced levels of thyroid hormone can lead to symptoms in multiple body systems. Some signs of hypothyroidism can include: hair loss (often on the trunk and flanks of both sides), dry brittle coat, obesity, listlessness, anemia, and even seizures.
Hypothyroidism is treated with an oral pill. This pill supplies thyroid hormone, and is usually given twice daily for the life of the dog. Periodic blood testing is recommended in order to gauge if the medication dose is too low or too high. Thyroid supplement is a safe medication, but if it is not given in a high enough dose, the patient will not be adequately treated. If the dose is too high, excessive water consumption, weight loss, and restlessness and high blood pressure can result. Once a pet is started on thyroid supplementation, it is recommended to check a thyroid level in two to three weeks, with the blood drawn between 4 to 6 hours after the morning dose. Once the correct dose is found, usually, no further testing of the thyroid level is required, unless problems arise.