Liothyronine: Price, Dosage & Where to Buy

Liothyronine is a thyroid hormone medicine containing synthetic triiodothyronine, also known as T3. It is most commonly prescribed as replacement treatment for hypothyroidism, when the body does not produce enough thyroid hormone. It requires a prescription in the United Kingdom and has been available as a generic medicine since 2005-08-17.

Liothyronine is used as replacement therapy for congenital or acquired hypothyroidism caused by a problem with the thyroid gland, pituitary gland or hypothalamus. It may also be used to help suppress thyroid-stimulating hormone as part of surgery and radioiodine therapy for well-differentiated thyroid cancer. A further use is as a diagnostic medicine in thyroid suppression tests, helping distinguish suspected mild hyperthyroidism from thyroid gland autonomy.

It is not indicated for suppressing benign thyroid nodules or non-toxic diffuse goitre in people with sufficient iodine, because overtreatment may cause hyperthyroidism. It is also not indicated for hypothyroidism during recovery from subacute thyroiditis. Thyroid hormones, including liothyronine, should not be used to treat obesity or for weight loss.

The label lists liothyronine sodium tablets in 5 mcg, 25 mcg and 50 mcg strengths, plus an intravenous solution of 10 ug/mL. The label lists oral administration once daily, with individual dosing based on response and laboratory findings. The usual starting dose is 25 mcg once daily for adults with hypothyroidism.

The usual starting dose is 5 mcg once daily for elderly patients or patients with underlying cardiac disease. The usual maintenance dose is 25 mcg to 75 mcg once daily. The usual starting dose is 5 mcg once daily for paediatric patients, with a 5 mcg increase every 3 to 4 days until the desired response.

The label lists 75 mcg to 100 mcg daily for 7 days for a thyroid suppression test. Dose changes require clinical and laboratory monitoring, and switching from levothyroxine begins with a low dose followed by gradual increases.

Liothyronine is a synthetic form of triiodothyronine, or T3, one of the body’s thyroid hormones. Thyroid hormones enter cells and influence how genetic instructions are used, helping regulate energy use, heat production, heart activity, digestion, growth and development. In hypothyroidism, replacing insufficient hormone helps restore thyroid hormone signalling and supports normal body processes.

Liothyronine acts directly as T3 rather than needing conversion from thyroxine, or T4. Its effects therefore depend on the amount reaching body tissues and on the sensitivity of those tissues.

Too much thyroid hormone can produce features of hyperthyroidism, including a fast heartbeat, palpitations, sweating, nervousness, tremor, diarrhoea and weight loss. The medicine has a narrow therapeutic index, so treatment is individually adjusted and monitored with clinical assessment and laboratory tests.

Experience with liothyronine use in pregnant women, including post-marketing data, has not reported increased rates of major birth defects or miscarriages. Untreated hypothyroidism can cause risks for the mother and fetus, so liothyronine should not be discontinued during pregnancy without medical advice. Pregnancy may increase thyroid hormone requirements, and serum TSH should be monitored with dosage adjusted as needed.

Limited published studies report that liothyronine is present in human milk, but there is insufficient information about effects on a breastfed infant or milk production. Discuss treatment with a doctor or pharmacist.

A missed dose can reduce the intended thyroid hormone replacement effect. General pharmacy practice is to follow the prescriber’s or pharmacist’s advice when a dose is remembered, and not to make an unplanned change or take extra medicine to compensate. Regular dosing supports stable treatment, but liothyronine has a narrow therapeutic index, so missed doses, repeated doses or changes in routine should be discussed with a pharmacist or doctor, particularly if symptoms develop.

Store liothyronine between 15°C and 30°C. Keep the medicine in its original packaging, protected from moisture and away from children. Follow the product label for any additional handling instructions to maintain quality.