From the Guidelines
Hypothyroidism should be treated with oral T4 monotherapy, specifically levothyroxine sodium, as it is the principal treatment for this condition. The treatment of hypothyroidism is crucial to alleviate symptoms and improve quality of life, as it is a condition where the thyroid gland doesn't produce enough thyroid hormones, requiring lifelong treatment with synthetic thyroid hormone replacement 1.
Diagnosis and Screening
The serum TSH test is the primary screening test for thyroid dysfunction, and multiple tests should be done over a 3- to 6-month interval to confirm or rule out abnormal findings 1. Follow-up testing of serum T4 levels in persons with persistently abnormal TSH levels can differentiate between subclinical and "overt" thyroid dysfunction.
Treatment and Management
The standard treatment is levothyroxine, typically started at a dose that is adjusted based on TSH levels checked 6-8 weeks after starting treatment, with a target TSH of 0.5-2.5 mIU/L for most adults. Common symptoms that should improve with treatment include fatigue, cold intolerance, weight gain, dry skin, constipation, and mental sluggishness. Regular monitoring with blood tests every 6-12 months is necessary to ensure proper dosing.
Special Considerations
Thyroid hormone is critical for metabolism, energy production, and proper function of virtually all body systems, which is why replacement therapy resolves symptoms when dosed correctly. Special considerations apply during pregnancy, when dose requirements typically increase and more frequent monitoring is needed. The USPSTF found no direct evidence that treatment of thyroid dysfunction based on risk level alters final health outcomes, but treatment is generally recommended for patients with a TSH level that is abnormal 1.
Key Points
- The principal treatment for hypothyroidism is oral T4 monotherapy (levothyroxine sodium) 1
- The serum TSH test is the primary screening test for thyroid dysfunction 1
- Treatment should be adjusted based on TSH levels checked 6-8 weeks after starting treatment 1
- Regular monitoring with blood tests every 6-12 months is necessary to ensure proper dosing 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 Maternal hypothyroidism during pregnancy is associated with a higher rate of complications, including spontaneous abortion, gestational hypertension, pre‑eclampsia, stillbirth, and premature delivery. Untreated maternal hypothyroidism may have an adverse effect on fetal neurocognitive development
Hypothyroidism Treatment: Levothyroxine sodium and liothyronine sodium are indicated for replacement or supplemental therapy in patients with hypothyroidism of any etiology.
- Key Points:
- Hypothyroidism should be treated promptly, especially during pregnancy.
- Untreated maternal hypothyroidism may have adverse effects on fetal neurocognitive development.
- Levothyroxine sodium dosage should be adjusted during pregnancy and returned to pre-pregnancy dose immediately after delivery 2.
- Liothyronine sodium can be used as replacement or supplemental therapy in patients with hypothyroidism, including pediatric patients, adults, and the elderly 3.
From the Research
Hypothyroidism Treatment
- The treatment of hypothyroidism with levothyroxine is effective and simple, but recommendations for the starting dose vary considerably 4.
- A full starting dose of levothyroxine in cardiac asymptomatic patients with primary hypothyroidism is safe and may be more convenient and cost-effective than a low starting dose regimen 4.
- 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 5.
Liothyronine Use
- 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 5.
- A trial of liothyronine/levothyroxine combined therapy may be warranted for some patients with confirmed overt hypothyroidism and persistent symptoms who have had adequate treatment with levothyroxine 5.
- The goals of combination therapy should be to achieve a physiological ratio of free triiodothyronine/free thyroxine and non-suppression of TSH 6.
Subclinical Hypothyroidism
- The diagnosis of subclinical hypothyroidism should be confirmed by repeat thyroid function tests ideally obtained at least 2 months later, as 62% of elevated TSH levels may revert to normal spontaneously 7.
- Generally, treatment is not necessary unless the TSH exceeds 7.0-10 mIU/L, and treatment does not improve symptoms or cognitive function if the TSH is less than 10 mIU/L 7.
- TSH goals are age-dependent, with a 97.5 percentile (upper limit of normal) of 3.6 mIU/L for patients under age 40, and 7.5 mIU/L for patients over age 80 7.
Combination Therapy
- Physiologic combinations of L-thyroxine plus liothyronine do not offer any objective advantage over L-thyroxine alone, yet patients prefer combination treatment 8.
- Combined treatment with levothyroxine and liothyronine may be preferred for some hypothyroid patients who are dissatisfied with treatment, especially those with a polymorphism in type 2 deiodinase 7.