What is the use of Euthyrox (levothyroxine)?

From the Guidelines

Euthyrox (levothyroxine) is used to treat hypothyroidism, a condition where the thyroid gland does not produce enough thyroid hormone, by replacing the missing hormone and restoring normal metabolism. The primary goal of levothyroxine therapy is to alleviate symptoms of hypothyroidism, such as fatigue, weight gain, cold intolerance, and depression, and to improve overall quality of life 1. Some key points to consider when using Euthyrox include:

• Dosing is highly individualized, usually starting at 25-50 mcg daily for adults with mild hypothyroidism, with gradual increases as needed based on thyroid function tests.
• It's essential to take Euthyrox consistently at the same time each day and avoid taking it with calcium, iron supplements, or certain foods that may interfere with absorption.
• Regular blood tests are necessary to monitor thyroid hormone levels and adjust dosage accordingly, as overtreatment can lead to adverse effects such as osteoporosis, fractures, and abnormal cardiac output 1.
• Patients should not switch between different brands of levothyroxine without medical supervision, as slight differences in formulation can affect hormone levels. The use of Euthyrox is supported by evidence from studies on the treatment of hypothyroidism, which have generally reported no indication of harms or minimal withdrawals from treatment due to adverse effects 1. However, it's crucial to carefully monitor patients and adjust treatment as needed to minimize the risk of overtreatment and its potential consequences.

From the FDA Drug Label

Levothyroxine sodium tablets are a L-thyroxine (T4) indicated in adult and pediatric patients, including neonates, for: • Hypothyroidism: As replacement therapy in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism. • Pituitary Thyrotropin (Thyroid‑Stimulating Hormone, TSH) Suppression: As an adjunct to surgery and radioiodine therapy in the management of thyrotropin-dependent well-differentiated thyroid cancer.

The use of Euthyrox (levothyroxine) is for:

• Hypothyroidism: as replacement therapy in primary, secondary, and tertiary congenital or acquired hypothyroidism
• Pituitary Thyrotropin (Thyroid-Stimulating Hormone, TSH) Suppression: as an adjunct to surgery and radioiodine therapy in the management of thyrotropin-dependent well-differentiated thyroid cancer 2

From the Research

Use of Euthyrox (Levothyroxine)

The use of Euthyrox, also known as levothyroxine, is primarily for the treatment of hypothyroidism, a condition where the thyroid gland does not produce enough thyroid hormones.

• Levothyroxine is used as replacement therapy in patients with hypothyroidism to normalize the serum thyroid-stimulating hormone (TSH) concentration 3, 4.
• The goal of levothyroxine therapy is to normalize the serum TSH concentration, which is usually achieved with a full replacement dosage of 1.6 micrograms/kg body weight per day 4.
• Levothyroxine is also used to suppress the serum TSH concentration in certain patients, such as those with benign solitary nonfunctioning thyroid nodules or a history of thyroid cancer 4.

Administration and Monitoring

• Levothyroxine can be administered orally in tablet or liquid form, with the liquid form being more rapidly absorbed and potentially more effective in maintaining normal TSH levels 5, 6.
• Monitoring of levothyroxine therapy is typically done through blood TSH assays, with dose adjustments made as needed to maintain a normal TSH level 3, 7.
• Certain factors, such as age, concurrent illnesses, and medications, can affect TSH levels and make it challenging to manage hypothyroidism 7.

Alternative Routes of Administration

• Alternative routes of levothyroxine administration, such as intravenous, intramuscular, and rectal, can be considered for patients with refractory hypothyroidism or those who have difficulty absorbing oral levothyroxine 6.
• These alternative routes may be effective in treating patients who have persistently elevated TSH levels despite oral levothyroxine therapy 6.