NHS Greater Glasgow & Clyde Area Drug and Therapeutics Committee
Greater Glasgow and Clyde Medicines
Medicines Update


Levothyroxine is included in the NHSGGC Adult Formulary preferred list and is the NHSGGC thyroid hormone of choice. It is cost-effective, suitable for once daily dosing due to its long half-life and provides stable and physiological levels of thyroid hormones for patients requiring replacement.


Liothyronine is not routinely recommended for prescribing as it has a much shorter half-life and steady-state levels cannot be maintained with once daily dosing.


The combination of levothyroxine and liothyronine as replacement therapy has not consistently been shown to be more beneficial than levothyroxine alone with respect to cognitive function, social functioning and wellbeing. Inappropriate variation in serum T3 may cause thyrotoxic symptoms, such as palpitations and tremor.


Liothyronine is available as licensed (and unlicensed) 20microgram tablets and unlicensed 5microgram tablets. Many other liothyronine-containing preparations, eg Armour Thyroid, are also unlicensed. The safety and quality of these products cannot be assured.


An audit of 21 patients prescribed liothyronine in primary care in NHSGGC showed that on rare occasions, specialists within the Board will recommend a patient receives liothyronine.


Before prescribing liothyronine, prescribers should consider the following:

  • Liothyronine is not a standard treatment. Liothyronine should only be used under the recommendation and care of an endocrinologist, where the patient has given informed consent and understands the risks of treatment
  • In line with MHRA advice, licensed products with the appropriate Marketing Authorisation should be used (within the licensed indications) to treat patients in preference to unlicensed medicines, off-label use or use of unlicensed specials
  • Liothyronine is an expensive medicine with a typical annual  cost of £365 , compared with £26 for levothyroxine
  • Patients prescribed liothyronine post-thyroidectomy to avoid interference with  radioiodine uptake scan should be switched to levothyroxine after the scan has been completed (as per recommendations from endocrinology/oncology)
  • Regular review of patients prescribed liothyronine is essential due to the risks and costs associated with treatment. Patients who do not show significant improvement should be switched to levothyroxine on the advice of an endocrinologist