What is the treatment for hypothyroidism (underactive thyroid)?

From the Guidelines

The primary treatment for hypothyroidism is oral T4 monotherapy, specifically levothyroxine sodium, which is taken as a daily oral medication. The treatment approach is based on the most recent and highest quality study available, which emphasizes the importance of thyroid hormone replacement therapy in managing hypothyroidism 1.

Key Considerations for Treatment

• The starting dose of levothyroxine is typically 1.6 mcg/kg/day for most adults, though lower doses (25-50 mcg/day) are recommended for elderly patients or those with cardiac disease.
• Levothyroxine should be taken on an empty stomach, 30-60 minutes before breakfast or 3-4 hours after the last meal of the day, to ensure optimal absorption.
• Certain medications and supplements (calcium, iron, antacids) can interfere with absorption, so they should be taken at least 4 hours apart from levothyroxine.
• Treatment is lifelong, and dosage is adjusted based on thyroid-stimulating hormone (TSH) levels, which should be checked 6-8 weeks after starting therapy or changing doses.
• The goal is to normalize TSH levels (typically 0.4-4.0 mIU/L), as guided by the most recent clinical recommendations 1.

Special Considerations

• Some patients may require combination therapy with liothyronine (T3) if symptoms persist despite normal TSH levels on levothyroxine alone, though this is less common.
• Regular monitoring is essential to ensure proper dosing and to avoid over-replacement, which can lead to symptoms of hyperthyroidism.
• The decision to treat subclinical hypothyroidism (TSH levels between 4.5 and 10 mIU/L) should be made on a case-by-case basis, considering the potential benefits and risks of therapy, as discussed in earlier guidelines 1.

Monitoring and Adjustment

• TSH levels should be monitored regularly to adjust the dosage of levothyroxine as needed.
• The treatment approach should be individualized, taking into account the patient's symptoms, medical history, and other factors that may influence the management of hypothyroidism.

From the FDA Drug Label

The general aim of therapy is to normalize the serum TSH level Levothyroxine sodium is indicated in patients from birth to less than 17 years of age: • As a replacement therapy in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism. Rapid restoration of normal serum T4 concentrations is essential for preventing the adverse effects of congenital hypothyroidism on cognitive development as well as on overall physical growth and maturation. Therefore, initiate levothyroxine sodium therapy immediately upon diagnosis. Levothyroxine is generally continued for life in these patients

The treatment for hypothyroidism (underactive thyroid) is levothyroxine sodium therapy, which aims to normalize the serum TSH level. It is indicated as a replacement therapy for primary, secondary, and tertiary congenital or acquired hypothyroidism, and is generally continued for life 2 2.

From the Research

Treatment Options for Hypothyroidism

The treatment for hypothyroidism typically involves lifelong hormone replacement therapy with synthetic thyroid hormone replacement medication, such as levothyroxine, to help regulate hormone levels in the body 3. The goal of the treatment is to normalize signs and symptoms, as well as to achieve thyroid-stimulating hormone (TSH) concentrations within the reference range, on an individual basis 4.

Levothyroxine Therapy

Levothyroxine sodium is the drug of choice for the treatment of hypothyroidism, even though the thyroid gland secretes both thyroxine and 3',3,5-triiodothyronine 5. Levothyroxine doses should be optimized aiming for a TSH in the 0.3-2.0 mU/L range for 3 to 6 months before a therapeutic response can be assessed 6.

Combination Therapy with Liothyronine

For patients who remain symptomatic on levothyroxine therapy, clinical guidelines recommend, on a trial basis, therapy with levothyroxine plus liothyronine (LT3) 6, 7. The decision to start treatment with liothyronine should be a shared decision between patient and clinician 6. Reducing the levothyroxine dose by 25 mcg/day and adding 2.5-7.5 mcg liothyronine once or twice a day is an appropriate starting point 7.

Key Considerations

• The use of liothyronine for hypothyroidism remains controversial, as numerous randomized trials have failed to show a benefit of treatment regimens that combine liothyronine with levothyroxine over levothyroxine monotherapy 6.
• Desiccated thyroid extract (DTE) is a form of combination therapy in which the levothyroxine/liothyronine ratio is approximately 4:1 7.
• Lifestyle modifications like eating healthy food and exercising regularly can help manage the symptoms and improve the quality of life 3.

Patient-Specific Factors

• Patients with confirmed overt hypothyroidism and persistent symptoms who have had adequate treatment with levothyroxine and in whom other comorbidities have been excluded may be considered for a trial of liothyronine/levothyroxine combined therapy 6.
• The goals of combination therapy should be to achieve a physiological ratio of free triiodothyronine/free thyroxine (FT3/FT4) and non-suppression of TSH 4.