Most people know someone who is affected by an underactive thyroid, but did you know that several different factors, including what medications you take, can impact thyroid function? 

Different drugs have different risk profiles. For example, the drug Amiodarone causes thyroiditis in about 10% of patients taking it. While on the other hand, most antineoplastic agents cause thyroid dysfunction in 20%–50% of patients, although some have even higher rates. 

In this article, we will discuss what drug-induced thyroiditis is, what causes it, and how to treat it – both conventionally and with an integrative practitioner. 

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What is Drug-Induced Thyroiditis?

Drug-induced thyroiditis is an inflammatory condition of the thyroid gland that occurs as a result of certain medications such as Amiodarone, interferons, lithium, and cytokines. This reaction can lead to either hypothyroidism or hyperthyroidism, which are common outcomes of drug-induced thyroid dysfunction characterized by an underactive or overactive thyroid gland, respectively (1). 

Common Medications Associated With Drug-Induced Thyroiditis

Several drugs can induce thyroiditis. These include:

Hyperthyroidism Medications

Hyperthyroidism medications, including propylthiouracil (PTU), methimazole, radioactive iodine (or radioiodine), and potassium iodide, are often used to control the overproduction of thyroid hormones. However, as a side effect, these medications can cause a drop in thyroid hormone levels. 

Amiodarone

Amiodarone, which is a drug prescribed to individuals with life-threatening heart arrhythmias, can result in both hyper or hypothyroidism.

Lithium

Used in treating bipolar disorder, lithium can trigger hypothyroidism, as it inhibits the thyroid gland from releasing thyroid hormone, or hyperthyroidism, from thyroiditis or, in rarer circumstances, Graves' Disease.

Medications for Cancer Treatment

Several medications used to treat cancer are linked with thyroiditis (4). 

Interleukin-2 

This drug is used to treat certain cancers, and a small percentage of users develop thyroiditis.

Tyrosine Kinase Inhibitors (TKIs)

Used to treat various cancers and leukemias, TKIs can induce hypothyroidism in up to 50% of patients. This may happen a few weeks to several months after starting the medication.

Interferon Alfa

Also used to treat various cancers and certain viral infections, interferon alfa may cause thyroiditis and induce the body to create antibodies that attack the thyroid gland.

Checkpoint Inhibitors

These drugs are used to boost the immune system's response against cancer cells. They can cause changes in various hormones throughout the body, including thyroid hormones.

Thalidomide 

While uncommon, some reports suggest that thalidomide, used to treat conditions such as multiple myeloma and leprosy, may cause hypothyroidism, though the exact mechanism is not well understood.

Somatostatin Analogues

These include drugs like octreotide, which can induce hypothyroidism by directly inhibiting TSH secretion.

Other medications that may cause thyroiditis include glucocorticoids, commonly used for inflammatory health conditions, and Bromocriptine, an alkaloid that can reduce serum TSH levels. Additionally, hormone medications, including exogenous estrogens used in estrogen replacement therapy and oral contraceptives, can also exacerbate hypothyroidism by increasing the concentration of thyroxine-binding globulin (4). 

Mechanisms Of Drug-Induced Thyroiditis

Drug-induced thyroiditis can manifest through several complex mechanisms. Some drugs, such as Amiodarone, have a unique capacity to induce both hyperthyroidism and hypothyroidism due to the iodine content, with type 1 amiodarone-induced hyperthyroidism increasing the synthesis and release of thyroid hormones and type 2 involving destructive thyroiditis leading to the release of preformed thyroid hormones from the damaged gland. Furthermore, immune modulators like checkpoint inhibitors predominantly induce hypothyroidism via a similar destructive thyroiditis mechanism, although instances of induced hyperthyroidism have also been reported. Lithium, known for its capacity to inhibit the secretion of thyroid hormones, can cause hypothyroidism while triggering a compensatory rise in thyroid-stimulating hormone (TSH) and potentially leading to thyroid enlargement or goiter. Tyrosine kinase inhibitors, such as sunitinib and lenvatinib, can induce thyroid abnormalities through mixed mechanisms, affecting multiple thyroid hormone production and regulation pathways. 

Functional Medicine Labs That Can Help Individualize Treatment for Drug-Induced Thyroiditis

Functional medicine labs offer a variety of tests that can help tailor treatment to patients, allowing providers to optimize management strategies.

Comprehensive Thyroid Panel 

Understanding how the thyroid is functioning is the first step in assessing drug-induced thyroiditis. A comprehensive thyroid panel, like the one offered by Access Medical Labs, measures key thyroid hormones, including TSH, T4, T3, and thyroid antibodies, helping to identify any imbalances.

Micronutrient Testing 

Micronutrient levels can influence thyroid health, as certain vitamins and minerals, such as zinc, selenium, and vitamin D, are essential for hormone synthesis and metabolism.

Stool Testing 

Our gut health can significantly influence our thyroid function due to the interconnectedness of these systems. A comprehensive stool test like the GI-MAP + Zonulin not only evaluates the presence of bacteria, such as H. pylori, linked with autoimmune thyroid conditions but also assesses markers of "leaky gut," a condition often seen in autoimmune disorders like thyroiditis. It also provides a detailed overview of the gut's microbiome, the community of microbes residing in the large intestine. Identifying and rectifying imbalances in these areas could be a key part of individualized treatment plans for drug-induced thyroiditis (7).

Stress Testing

Chronic stress can disrupt hormone balance and contribute to thyroid dysfunction. The Ayumetrix adrenal stress panel measures key stress hormones, offering insights into how stress might be influencing thyroid health.

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Conventional Medical Management of Drug-Induced Thyroiditis

The approach to managing drug-induced thyroiditis hinges primarily on the specific medication causing the condition. Your healthcare provider may choose to replace the problematic drug with an alternate, yet similar, medication in an effort to mitigate thyroiditis. If you have hypothyroidism, your provider might opt to administer levothyroxine, a medication that replaces or provides more thyroid hormone, while you continue on the medication that's inducing thyroiditis. On the other hand, if you have hyperthyroidism, your provider may prescribe beta-blockers and methimazole or glucocorticoids, depending on the type of thyroiditis. These alternative pathways allow for the treatment of thyroiditis without completely discontinuing the necessary original medication (1,15).

Integrative Approaches to Drug-Induced Thyroiditis

Integrative approaches to drug-induced thyroiditis often include a focus on diet, nutrition, and supplementation. 

Role Of Diet And Nutrition in The Treatment of Drug-Induced Thyroiditis

Although there isn't a specific diet that directly aids in the treatment of drug-induced thyroiditis, maintaining a wholesome diet can play a significant role in upholding thyroid health (7).

A well-rounded dietary regimen, which includes an emphasis on anti-inflammatory nutrients, can contribute towards better thyroid functionality and overall health. Special attention to the intake of nutrients like vitamin D and melatonin could be instrumental in preserving thyroid function amidst chronic inflammation, especially for those predisposed to autoimmune disorders (19). 

Moreover, those on thyroid hormone medication should be wary of foods high in soy protein, as excess soy might disrupt the absorption of thyroid hormones. Excessive consumption of iodine should also be avoided. A balanced diet that includes a variety of fruits, vegetables, nuts, and whole grains can not only boost your thyroid's well-being once it returns to normal levels but also facilitate the smooth functioning of your digestive system and the efficient pumping of your heart—both vital for a healthy metabolism.

Reducing the intake of saturated fats, trans fats, and simple carbohydrates while focusing on complex carbohydrates found in whole-grain foods, fruits, and vegetables is advised. An increase in dietary fiber, obtained from whole-grain foods and a diverse array of vegetables and fruits, can further assist in improving digestion. In conclusion, although no specific diet exists for drug-induced thyroiditis, embracing a healthy eating pattern and complying with nutritional guidelines can be a potent strategy for managing this condition (22). 

Supplements and Herbs That Can Assist With The Treatment of Drug-Induced Thyroiditis

While there are no specific supplements or herbs that are helpful in treating drug-induced thyroiditis, some herbs may help optimize thyroid function by interacting with the hormones that are already present in your body.

Ashwagandha for Thyroiditis

Although research is limited, the use of Ashwagandha has a potential role in managing thyroiditis. Studies have shown that regular intake of Ashwagandha can significantly improve thyroid hormone levels in those suffering from subclinical hypothyroidism (4).

Dose: 600 mg daily

Duration: 8 weeks

L-Carnitine for Thyroiditis

L-carnitine, an amino acid derivative, can play a helpful role in managing thyroiditis, particularly when the thyroid is overactive. It works by blocking the actions of thyroid hormones within cells, helping to reduce the symptoms of hyperthyroidism. Notably, it has been effectively used in severe cases, indicating its potential as part of the overall strategy for treating thyroid conditions.

Dose: 2-4 grams per day

Duration: Ongoing

Vitamin D for Thyroiditis

Research indicates that individuals with hypothyroidism often exhibit vitamin D deficiency and low calcium levels, which are linked to the severity of their thyroid dysfunction. Vitamin D plays an important role in immune modulation, helping to reduce inflammation often associated with thyroiditis. Supplementation with vitamin D has been shown to improve thyroid-stimulating hormone levels (TSH) and calcium concentrations. Given its positive effects on inflammation and thyroid hormone regulation, it is recommended that hypothyroid patients are screened for vitamin D deficiency, as supplementation could help decrease their risk of hypothyroidism (4).

Dose: 50,000 IU weekly

Duration: 12 weeks

Importance Of Communication And Collaboration Between All Healthcare Providers (Integrative and Conventional)

Effective treatment of drug-induced thyroiditis heavily relies on seamless teamwork among all healthcare providers - both conventional and integrative. Each brings unique insights to the table: conventional doctors have detailed knowledge about medications and their effects, while integrative doctors might offer alternative therapies and lifestyle modifications. When they collaborate, they can create a personalized treatment strategy that not only reduces side effects but also boosts overall health. Medication management becomes more precise in this setup, which is an essential part of controlling symptoms and preventing further complications. It's important for patients not to start any supplements or alternative treatments without consulting all healthcare providers, as these can interact with ongoing treatments. Continuous communication among all involved allows swift adjustments in response to any changes in the patient's health. Thus, the synergy between conventional and integrative healthcare providers is vital in delivering the most effective care to those managing drug-induced thyroiditis.

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Summary

In summary, drug-induced thyroiditis is an inflammation of the thyroid that results in altered function of the thyroid gland caused by ingesting certain medications. Common offending medications include drugs like Amiodarone, LIthium, or anti-cancer drugs. Functional medicine tests can help doctors to improve thyroid function by understanding hormone balance, nutrient levels, gut health, and the stress response – all factors which can impact the thyroid's function. Treatment typically involves changing the problematic medication or adding thyroid hormone replacement. All in all, a healthy diet and supplements such as L-carnitine and vitamin D can also support overall thyroid health.