Thyroid disorders and management

The thyroid is the small gland in the front of the neck that wraps around the windpipe. It produces hormones that help to regulate the cells of the body.¹

Thyroid issues usually occur when the gland becomes overactive (hyperthyroidism) or underactive (hypothyroidism). An incorrectly functioning thyroid can lead to hormones not being regulated properly.

Pharmacy plays an important role in the management and correct use of thyroid medications.

Role of the thyroid

The thyroid gland is an integral part of the endocrine system, responsible for hormone production. The hormones it produces help control the body’s metabolic processes. These hormones are thyroxine (T4), triiodothyronine (T3) and calcitonin.

The main hormone produced by the thyroid is T4, which is then changed into T3, the active thyroid hormone.² T4 and T3 help to control energy levels, body temperature, metabolism, the health of muscles and bones, and brain development.² Calcitonin aids in controlling the amount of calcium and phosphate within the body.

Thyroid issues 

Common thyroid issues include:

• Hyperthyroidism.
• Hypothyroidism.
• Graves’ disease.
• Thyroid nodules.

Hypothyroidism occurs when the thyroid gland is underactive, meaning it fails to produce enough hormones. Symptoms can include sensitivity to the cold, fatigue, dry skin, constipation, weight gain, depression, irregular periods, swollen face and difficulty becoming pregnant. Hypothyroidism is treated through thyroxine replacement therapy.²

Hyperthyroidism occurs when the thyroid is overactive, meaning that hormones are overproduced. Hyperthyroidism is most commonly caused by Graves’ disease, an abnormality in the immune system.³ The symptoms of Graves’ disease include thyroid eye disease, eye swelling and coarsening, and reddening of the skin on the shins. Hyperthyroidism can be diagnosed through a blood test that measures the levels of thyroid hormones within the body.³

Thyroid nodules are solid fluid-filled lumps, formed within the thyroid, that can cause hyperthyroidism. In most cases, thyroid nodules are not serious. However, a small percentage of them can be cancerous or cause the increased production of the T4 hormone.⁴ This can cause weight loss, increased sweating, tremors, nervousness and rapid and irregular heartbeat.⁴ 

Iodine deficiency and supplementation 

Iodine, an important element in the proper functioning of the thyroid gland, is present in seawater and within the soil. In Australia, a relatively low level of iodine is found within the soil where food is grown and livestock grazes.⁵

Iodine deficiency is the most common cause of thyroid disorders and occurs when not enough iodine is present in the diet. Such deficiency can cause hyperthyroidism, due to the thyroid becoming enlarged.⁵ Iodine can be found within iodine-enriched foods such as dairy products, seafood and iodised salt, and in iodine supplements.

“To protect your family from iodine deficiency and the consequences of a sluggish thyroid function, ensure you include iodine-enriched foods on your shopping list,” Australian Thyroid Foundation CEO Beverley Garside said.⁶

The thyroid hormone has a particularly important role in the normal development of the brain and nervous system before birth, in babies, and in young children.⁷ Taking 220µg per day of iodine is recommended for pregnant women and 250µg per day for breastfeeding mothers.⁷ The National Health and Medical Research Council recommends that all women who are pregnant, breastfeeding or considering pregnancy take an iodine supplement of 150µg per day.⁷

Medicines 

In the management of thyroid issues, medication plays an important role. Thyroid medications work through either replacing the missing hormone in the case of hypothyroidism or blocking the hormone product in the case of hyperthyroidism to prevent the body from producing too much of the thyroid hormone.⁸

There is no cure for hyperthyroidism. However, it can be managed through several medications that block hormone production in the thyroid gland. All these medications are covered under the PBS, but some brands cost more than others.⁸

For those diagnosed with hypothyroidism, medicines are usually prescribed to replace the hormones. Levothyroxine is commonly used to replace the T4 hormone, and liothyronine is used to replace the T3 hormone.⁸ Multiple different brands of levothyroxine tablets are available, but not all brands can be substituted, and some need to be stored in the fridge. Ensuring patients are aware of this is important for the correct use and storage of the medicines.⁸

References: 

1. Hormones Australia. ‘Thyroid gland’. 2023. hormones-australia.org.au/the-endocrine-system/thyroid/.
2. ‘Thyroid gland’. 2023. healthdirect.gov.au/thyroid-gland.
3. Better Health Channel. ‘Thyroid – hyperthyroidism’. 2011. vic.gov.au/health/conditionsandtreatments/thyroid-hyperthyroidism#graves-disease
4. Mayo Clinic. ‘Thyroid nodules’. 2022. org/diseases-conditions/thyroid-nodules/symptoms-causes/syc-20355262.
5. Australian Thyroid Foundation. ‘Iodine Deficiency’. 2023. org.au/Iodine-Deficiency.
6. Australian Thyroid Foundation. ‘Avoid Iodine Deficiency with Healthy Food Choices’. thyroidfoundation.org.au/news/13186421.
7. National Health and Medical Research Council. ‘Iodine supplementation for pregnant and breastfeeding women’. 2010. gov.au/about-us/publications/iodine-supplementation-pregnant-and-breastfeeding-women#block-views-block-file-attachments-content-block-1.
8. ‘Thyroid medicines’. 2023. healthdirect.gov.au/thyroid-medicines.

This feature was originally published in the November issue of Retail Pharmacy magazine.