What is the recommended treatment for a patient with hypothyroidism (underactive thyroid gland)?

From the Guidelines

The recommended treatment for hypothyroidism is synthetic thyroid hormone replacement, primarily with levothyroxine (T4) taken as a daily oral medication. The typical starting dose for adults is 1.6 mcg/kg body weight per day (usually 50-125 mcg), taken on an empty stomach 30-60 minutes before breakfast or at bedtime, at least 4 hours apart from medications or supplements containing calcium, iron, or aluminum. Dosage is adjusted based on thyroid-stimulating hormone (TSH) levels, which should be checked every 6-8 weeks initially until stabilized, then annually. Treatment is typically lifelong, as hypothyroidism is usually permanent. Some patients may require combination therapy with liothyronine (T3) if symptoms persist despite normal TSH levels on levothyroxine alone. Medication effectiveness can be affected by certain foods, medications, and supplements, so consistent timing and administration are important. Hormone replacement works by restoring normal thyroid hormone levels, which regulate metabolism, energy production, and numerous bodily functions. Most patients experience improvement in symptoms like fatigue, cold intolerance, and weight gain within 2-4 weeks of starting appropriate treatment, as noted in studies such as 1.

Key Considerations

• The principal treatment for hypothyroidism is oral T4 monotherapy (levothyroxine sodium) 1.
• Treatment is generally recommended for patients with a TSH level that is undetectable or less than 0.1 mIU/L, particularly those with overt Graves disease or nodular thyroid disease 1.
• The optimal screening interval for thyroid dysfunction is unknown, and evidence that screening improves important health outcomes is lacking 1.
• Long-term randomized, blinded, controlled trials of screening for thyroid dysfunction would provide the most direct evidence on any potential benefits of this widespread practice 1.

Administration and Monitoring

• Levothyroxine should be taken on an empty stomach, at least 4 hours apart from medications or supplements containing calcium, iron, or aluminum.
• TSH levels should be checked every 6-8 weeks initially until stabilized, then annually.
• Dosage adjustments should be made based on TSH levels to maintain normal thyroid hormone levels.

Potential Risks and Benefits

• Treatment of thyroid dysfunction may not alter final health outcomes, and the effects of treatment on important clinical outcomes may be independent of any known intermediate outcomes 1.
• Overdiagnosis and overtreatment are concerns, particularly in asymptomatic patients, and may lead to unnecessary treatment and potential harms 1.

From the FDA Drug Label

Thyroid hormone drugs are indicated: As replacement or supplemental therapy in patients with hypothyroidism of any etiology, except transient hypothyroidism during the recovery phase of subacute thyroiditis 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.

The recommended treatment for a patient with hypothyroidism is replacement therapy with thyroid hormone drugs, such as levothyroxine sodium or liothyronine sodium.

• Levothyroxine sodium is indicated for replacement therapy in primary, secondary, and tertiary congenital or acquired hypothyroidism.
• Liothyronine sodium is indicated as replacement or supplemental therapy in patients with hypothyroidism of any etiology. The treatment should be initiated immediately upon diagnosis and closely monitored to prevent adverse effects on cognitive development and overall physical growth and maturation 2, 3.

From the Research

Treatment Overview

• The recommended treatment for hypothyroidism is levothyroxine (LT4) monotherapy, which is the standard of care 4, 5, 6.
• Levothyroxine replacement therapy is started at a dose of 1.5 to 1.8 mcg per kg per day, with adjustments made based on thyroid-stimulating hormone (TSH) levels and symptom relief 5, 6.
• Patients older than 60 years or with known or suspected ischemic heart disease should start at a lower dosage of levothyroxine (12.5 to 50 mcg per day) 5.

Combination Therapy

• There is no strong evidence to support the use of combination therapy with levothyroxine (LT4) and triiodothyronine (LT3) for patients with hypothyroidism 4, 7.
• Some studies suggest that combination therapy may be beneficial for individual patients with specific characteristics, such as polymorphisms in deiodinase enzymes, but more research is needed to confirm this 4, 7.
• The current guideline-based management of hypothyroidism recommends monotherapy with levothyroxine (LT4), titrated to maintain the level of thyrotropin within a euthyroid reference range 7.

Special Considerations

• Women with hypothyroidism who become pregnant should increase their weekly dosage of levothyroxine by 30% up to nine doses per week, followed by monthly evaluation and management 5.
• Patients with persistent symptoms after adequate levothyroxine dosing should be reassessed for other causes or the need for referral 5, 6.
• Early recognition of myxedema coma and appropriate treatment is essential 5.

Diagnosis and Follow-up

• Diagnosis of hypothyroidism relies on simple-to-obtain, fairly inexpensive testing of thyroid-stimulating hormone (TSH) levels and confirmation with levels of thyroxine 5, 6.
• Follow-up involves regular assessment of levels of TSH and symptom relief 6.
• Most patients with subclinical hypothyroidism do not benefit from treatment unless the thyroid-stimulating hormone level is greater than 10 mIU per L or the thyroid peroxidase antibody is elevated 5.