From the Guidelines
Myxedema is treated with thyroid hormone replacement therapy, primarily using levothyroxine (T4), with a standard starting dose for adults of 1.6 mcg/kg/day, which translates to about 100-125 mcg daily for most adults, as recommended by the USPSTF 1. The goal of treatment is to achieve a TSH level within the normal reference range (typically 0.4-4.0 mIU/L) and to alleviate symptoms of hypothyroidism, such as fatigue, cold intolerance, and dry skin. Some key points to consider in the treatment of myxedema include:
- The medication should be taken on an empty stomach, 30-60 minutes before breakfast, to ensure optimal absorption.
- Treatment is lifelong, and dosage adjustments are made based on thyroid function tests (TSH levels), which should be checked 6-8 weeks after starting therapy or changing doses.
- Patients should be monitored for symptoms of both under-replacement (persistent fatigue, cold intolerance) and over-replacement (palpitations, anxiety, insomnia).
- In elderly patients or those with cardiac disease, a lower starting dose of 25-50 mcg daily is recommended with gradual increases every 4-6 weeks.
- Levothyroxine works by replacing the thyroid hormone that the body cannot produce in sufficient quantities, thereby reversing the metabolic slowdown that characterizes myxedema.
- In severe cases of myxedema coma, intravenous levothyroxine may be required along with supportive care in an intensive care setting. It is essential to note that while the USPSTF recommends the use of levothyroxine for the treatment of hypothyroidism, there is limited evidence on the effectiveness of treatment in asymptomatic individuals with subclinical thyroid dysfunction 1.
From the FDA Drug Label
Myxedema Recommended starting dosage is 5 mcg daily This may be increased by 5 to 10 mcg daily every 1 or 2 weeks. When 25 mcg daily is reached, dosage may be increased by 5 to 25 mcg every 1 or 2 weeks until a satisfactory therapeutic response is attained. Usual maintenance dose is 50 to 100 mcg daily The treatment of myxedema involves the administration of liothyronine (T3), with a recommended starting dosage of 5 mcg daily. The dosage may be increased by 5 to 10 mcg daily every 1 or 2 weeks, and when 25 mcg daily is reached, the dosage may be increased by 5 to 25 mcg every 1 or 2 weeks until a satisfactory therapeutic response is attained. The usual maintenance dose is 50 to 100 mcg daily 2.
From the Research
Treatment Options for Myxedema Coma
- Myxedema coma is a severe complication of hypothyroidism that can be life-threatening if not treated promptly and effectively 3, 4, 5, 6.
- Treatment options for myxedema coma include:
- Oral levothyroxine: This can be an effective option in resource-limited settings where intravenous thyroid hormone replacement is not available 3.
- Intravenous triiodothyronine (T3) or intravenous thyroxine (T4): These are commonly used to treat myxedema coma, especially in severe cases 4, 5, 6.
- Combination therapy with levothyroxine and liothyronine: This has been shown to be effective in treating myxedema coma and improving quality of life 5, 7.
- Hydrocortisone: This should be administered until coexisting adrenal insufficiency is ruled out 4, 6.
Important Considerations
- Early diagnosis and treatment are crucial to achieve a favorable outcome in myxedema coma 3, 5.
- Thyroid function tests (TFTs) should be monitored closely in individuals with hypothyroidism and diarrhea due to the risk of thyroxine malabsorption 4.
- A thyroxine absorption test can be used to confirm thyroxine malabsorption in individuals with persistent hypothyroidism 4.
- Intensive supportive care, including pulmonary and cardiovascular support, is essential in the treatment of myxedema coma 5, 6.