Thyroid and Parathyroid Drug Therapy

The thyroid and parathyroid glands produce hormones responsible for metabolism, growth, and development. The thyroid gland produces the thyroid hormones T3, or triiodothyronine, and T4, or thyroxine. Thyroid medications are primarily used to treat hypothyroidism which is a decrease in thyroid hormones; and hyperthyroidism, which is an increase in these thyroid hormones.

The parathyroid glands, on the other hand, produce parathyroid hormone, or PTH for short. So parathyroid disorders include hypoparathyroidism, which is a decrease in PTH, and hyperparathyroidism, which is an increase in PTH. Let's start with the treatment for hypothyroidism, which often presents with weight gain, weakness, fatigue, and cold intolerance. Treatment involves thyroid hormone replacement therapy with levothyroxine, which is a synthetic form of T4.

In contrast, hyperthyroidism presents with weight loss, anxiety, an elevated heart rate and blood pressure, as well as bulging eyes, or exophthalmos. Hyperthyroidism is treated with methimazole or propylthiouracil, which suppress the synthesis of thyroid hormones. Now, hypoparathyroidism, will often present with signs and symptoms of hypocalcemia, like numbness in the hands, feet, and mouth, as well as cardiac arrythmias and tetany, or involuntary muscle cramps. It's treated with calcitriol, or vitamin D3, which increases blood calcium levels.

In contrast, hyperparathyroidism presents with signs and symptoms of hypercalcemia, which can be remembered by 'stones, bones, abdominal groans, and psychiatric overtones' meaning kidney stones, osteoporosis, abdominal pain and constipation, and depression and fatigue. It can be treated with cinacalcet, which decreases blood calcium levels.

As far as side effects go, levothyroxine can cause headaches, insomnia, nausea, and weight loss, as well as hyperthyroidism. Importantly, it has a Black Box warning that it should not be used for weight loss. Side effects of methimazole and propylthiouracil include headaches, nausea, skin rash, as well as hypothyroidism. Hepatitis and jaundice can also occur. In fact, propylthiouracil has a Black Box warning for being highly hepatotoxic, potentially causing severe liver injury and acute liver failure. Now, the most common side effects of calcitriol are headache, drowsiness, and dry mouth, as well as nausea, vomiting, and constipation. Other important side effects include hypertension, cardiac arrhythmias, as well as hypercalcemia.

Common side effects of cinacalcet include anorexia, nausea, vomiting, and diarrhea, and hypocalcemia.

Alright, when caring for a patient with a thyroid or parathyroid disorder, obtain a baseline assessment, including weight and vital signs, noting any changes in blood pressure, temperature, and heart rate. Also assess for specific symptoms related to their diagnosis. Then, review your patient's most recent laboratory test results, including CBC, thyroid hormones, thyroid stimulating hormone, and PTH levels, liver and renal function tests, as well as calcium, phosphorus, magnesium, and vitamin D levels.

When providing education, focus your teaching on safe medication self-administration. Be sure they understand why their medication is prescribed, and teach them to take their medication exactly as prescribed. For example, for patients prescribed levothyroxine, instruct them to take the medication with plenty of water on an empty stomach, at least 30 to 60 minutes before breakfast and 3 to 4 hours before taking other medications.

Let them know about the side effects they could experience, and instruct them to seek emergency medical treatment immediately if symptoms of hyper- or hypocalcemia or hyper- or hypothyroidism occur. Also teach them to immediately contact their health care provider if their symptoms don't resolve or get worse. Finally, emphasize the importance of continuing their medication as prescribed, and to never abruptly stop treatment.

Alright, as a quick recap… The hormones produced by the thyroid and parathyroid glands are responsible for metabolism, growth, and development.

Commonly used medications for thyroid and parathyroid disorders include levothyroxine, which is a synthetic form of T4; methimazole and propylthiouracil, which suppress the synthesis of thyroid hormone; calcitriol, or vitamin D3, which increases blood calcium levels, and cinacalcet which decreases blood calcium levels.

Nursing considerations for thyroid and parathyroid medication therapy include establishing a baseline assessment, monitoring for side effects, evaluating the effectiveness of therapy, and providing teaching for safe self-administration.