From the Guidelines
A patient may be on levothyroxine 88 µg and liothyronine 5 µg as part of combination thyroid hormone replacement therapy, which is typically used when a patient has hypothyroidism and continues to experience symptoms despite adequate treatment with levothyroxine alone. This approach is based on the principle of mimicking the natural production of both hormones by a healthy thyroid gland. The specific doses (88 µg of levothyroxine and 5 µg of liothyronine) are individualized based on the patient's thyroid function tests, symptoms, and response to treatment 1.
Indications for Combination Therapy
The principal treatment for hypothyroidism is oral T4 monotherapy (levothyroxine sodium) 1. However, some patients may have difficulty converting T4 to the active form T3 (liothyronine) in their tissues, which may necessitate combination therapy. The indications for combination therapy include:
- Hypothyroidism with persistent symptoms despite adequate treatment with levothyroxine alone
- Difficulty converting T4 to T3 in tissues
- Need for individualized treatment based on thyroid function tests, symptoms, and response to treatment
Monitoring and Side Effects
Patients on combination therapy should have regular monitoring of thyroid function tests (TSH, free T4, and sometimes free T3) to ensure proper dosing 1. Side effects of excessive thyroid hormone replacement include heart palpitations, anxiety, insomnia, and bone loss, so careful dosing and monitoring are essential. Some patients report improved energy levels, cognitive function, and overall well-being with combination therapy compared to levothyroxine alone.
Key Considerations
The optimal screening interval for thyroid dysfunction is unknown, and the USPSTF found no direct evidence that treatment of thyroid dysfunction based on risk level alters final health outcomes 1. However, 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.
From the Research
Indication for Levothyroxine (T4) and Liothyronine (T3) Therapy
The indication for a patient to be on levothyroxine (T4) 88 micrograms and liothyronine (T3) 5 micrograms is not explicitly stated in the provided studies. However, the following points can be considered:
- Levothyroxine (T4) is the standard treatment for hypothyroidism, and the dose is typically adjusted based on the patient's thyroid-stimulating hormone (TSH) levels 2, 3, 4.
- Liothyronine (T3) is sometimes added to levothyroxine (T4) therapy in patients who remain symptomatic despite normal TSH levels, although the evidence for this approach is limited 2, 5.
- The combination of levothyroxine (T4) and liothyronine (T3) may be beneficial for patients with certain genetic polymorphisms, such as the DIO2 gene 5.
- Some studies suggest that adding liothyronine (T3) to levothyroxine (T4) therapy may not provide significant benefits for most patients with hypothyroidism 6.
Key Considerations
Some key considerations for levothyroxine (T4) and liothyronine (T3) therapy include:
- Accurate diagnosis of hypothyroidism and identification of patients who are likely to benefit from therapy 6.
- Monitoring of TSH levels and adjustment of levothyroxine (T4) dose as needed 3, 4.
- Potential benefits and risks of adding liothyronine (T3) to levothyroxine (T4) therapy, including the risk of adverse effects such as thyrotoxicosis 2, 5.
- Individualization of therapy based on patient symptoms, genetic polymorphisms, and other factors 5, 6.