From the FDA Drug Label
Thyroid hormone drugs are natural or synthetic preparations containing tetraiodothyronine (T4, levothyroxine) sodium or triiodothyronine (T3, liothyronine) sodium or both. Liothyronine Sodium Tablets, USP contain liothyronine (L-triiodothyronine or LT3), a synthetic form of a natural thyroid hormone, and is available as the sodium salt.
Liothyronine is a synthetic thyroid hormone that is available as the sodium salt. It is used as a replacement for the natural thyroid hormone, triiodothyronine (T3).
- The drug is available in tablet form, with each tablet containing 5 mcg, 25 mcg, or 50 mcg of liothyronine sodium.
- The inactive ingredients in the tablet include calcium sulfate, microcrystalline cellulose, hypromellose, talc, and colloidal silicon dioxide 1.
From the Research
Liothyronin should be considered for patients with hypothyroidism who remain symptomatic on levothyroxine (LT4) therapy, with a starting dose of 2.5-7.5 mcg once or twice a day, in combination with a reduced LT4 dose. This approach is supported by recent studies, including a 2023 consensus statement from the British Thyroid Association and the Society for Endocrinology 2, which suggests that a trial of combination therapy with LT4 and liothyronine may be warranted for patients with confirmed overt hypothyroidism and persistent symptoms who have had adequate treatment with LT4.
When prescribing liothyronin, it's essential to monitor thyroid function tests regularly to ensure proper dosing and minimize the risk of adverse effects, such as heart palpitations, anxiety, and insomnia. The medication works by directly replacing the active T3 hormone, which regulates metabolism, energy production, and various bodily functions throughout the body.
Some key points to consider when using liothyronin include:
- Starting with a low dose and adjusting based on patient response and lab results
- Maintaining consistent hormone levels by taking the medication at the same time each day
- Monitoring for potential side effects, particularly if doses are too high
- Considering combination therapy with LT4 for patients who remain symptomatic on LT4 monotherapy, as supported by recent studies 3, 2
It's also important to note that the current evidence does not support the use of liothyronine as a first-line treatment for hypothyroidism, but rather as an adjunct to LT4 therapy for patients who have not responded adequately to LT4 monotherapy 4, 5, 6.