NHS England and NHS Confederation policy guidance, Items which should not routinely be prescribed in primary care: policy guidance, recommends that:

• Liothyronine should only be initiated by an NHS consultant endocrinologist when being prescribed for the treatment of hypothyroidism.
• Liothyronine should be prescribed only if no alternative intervention or medicine is clinically appropriate or available for the patient.
• Patients taking liothyronine for the treatment of hypothyroidism who have not already been reviewed, should be reviewed by an NHS consultant endocrinologist.

This advice for prescribers helps implement these policy recommendations, and is for:

• prescribers in all care settings
• NHS consultant endocrinologists, psychiatrists and their teams
• people with thyroid disease and/or depression, their families and carers.

It may also be helpful to:

• organisations commissioning NHS services
• providers of NHS services, including secondary care organisations.

This advice updates and replaces that developed in 2019 by the South Regional Medicines Optimisation Committee (RMOC).

For background information on why liothyronine is not routinely recommended for prescribing, please see the joint British Thyroid Association (BTA) and Society of Endocrinologists (SoC) consensus statement and NICE guideline: Thyroid disease: assessment and management.

Liothyronine for hypothyroidism

Hypothyroidism is caused by deficiency of thyroid hormones, which are essential for normal growth, development and metabolism. It can usually be treated effectively with levothyroxine (L-T4) alone. However, a small proportion of patients treated with levothyroxine continue to have symptoms despite adequate biochemical correction. For these patients, oral liothyronine (triiodothyronine; L-T3) may be appropriate.

Neither NICE nor the joint NHS England and NHS Confederation guidance recommends routine prescribing of liothyronine as monotherapy or in combination with levothyroxine; however, both recognise that a small proportion of patients may benefit from liothyronine.

This prescribing advice sets out how liothyronine may be reviewed and then withdrawn or continued, or initiated.

In all cases, the patient and the prescriber should take a shared decision-making approach to reach a decision about the most appropriate treatment for the patient, taking into account the patient’s values and preferences.

Patients currently prescribed liothyronine

Patients who have already had a review by an NHS consultant endocrinologist should continue to be prescribed liothyronine under existing arrangements.

Reviewing liothyronine

Patients who have not had a review and are already established on liothyronine as monotherapy or in combination with levothyroxine should have a review by an NHS consultant endocrinologist. 

The NHS consultant endocrinologist should:

• review the patient and consider switching to levothyroxine monotherapy where clinically appropriate
• not routinely withdraw liothyronine for patients who feel well on liothyronine with a serum thyroid stimulating hormone (TSH) within the reference range (see BTA and SoC joint consensus statement)
• consider, for people stable on combination therapy, trialling levothyroxine monotherapy to see whether the liothyronine is still benefiting them
• advise primary care prescribers on reviewing or adjusting a patient’s treatment where this is the responsibility of the primary care prescriber.

Liothyronine prescriptions should continue until the NHS consultant endocrinologist review has taken place.

Withdrawing and stopping liothyronine (including switching from liothyronine to levothyroxine)

After a review, if the decision is to withdraw liothyronine prescribed as monotherapy or in combination with levothyroxine, withdrawal should be gradual in line with NHS consultant endocrinologist recommendations and may take many months to complete.

Please note:

• Liothyronine should not be stopped abruptly.
• Dose conversion advice can be found in the BTA and SoC joint consensus statement.

Continuing liothyronine

If the decision after a 3-month or longer review by an NHS consultant endocrinologist is to continue liothyronine as monotherapy or in combination with levothyroxine, primary care repeat prescribing would be reasonable in line with any local shared care arrangements (Responsibility for prescribing between primary and secondary/tertiary care and Shared care for medicines guidance, a standard approach).

When liothyronine is clinically appropriate:

• follow the British National Formulary (BNF) and the Summary of Product Characteristics (SmPC) for prescribing and monitoring information
• prescribe the formulation with the lowest acquisition cost (see the BNF and PrescQIPP) specific patient factors require another formulation.

New patients

Liothyronine as monotherapy or in combination with levothyroxine should only be initiated by an NHS consultant endocrinologist, and only if the patient’s symptoms persist while taking levothyroxine.

A small number of patients who take levothyroxine have persistent symptoms despite their TSH remaining in the reference range. Before initiating liothyronine, consider excluding other potential causes of persistent symptoms:

• Rule out other conditions (see BTA and SoC joint consensus statement)
• Confirm with the patient that they are taking their levothyroxine as intended:
• check the patient’s adherence to their levothyroxine
• establish the frequency of any missed doses.
• check that levothyroxine is taken at least 1 hour before food (including dietary fibre, milk and soya products) and 4 hours before or after antacids, calcium or iron supplements
• establish whether there have been any changes in the patient’s levothyroxine tablet formulations
• consider consistently prescribing a specific product known to be well tolerated by the patient. If symptoms or poor control of thyroid function persist (despite adhering to a specific product), consider prescribing levothyroxine oral solution as per MHRA
• In some cases, a retrospective review of the original diagnosis of overt hypothyroidism may be necessary. If there is no biochemical evidence of overt hypothyroidism, a gradual withdrawal of all thyroid hormone preparations is indicated.

If a patient is initiated on liothyronine, prescribing responsibility should remain with the NHS consultant endocrinologist for at least 3 months. After this 3-month period, if the decision is to continue liothyronine, then repeat prescribing in primary care may be reasonable in line with any local shared care arrangements (Responsibility for prescribing between primary and secondary/tertiary care and Shared care for medicines guidance, a standard approach).

Please note:

• For patients who trial liothyronine treatment but this shows no evidence of ongoing clinical benefit, treatment should be discontinued and the patient prescribed levothyroxine monotherapy (see BTA and SoC joint consensus statement).
• Dose conversion advice can be found in BTA and SoC joint consensus statement).

When liothyronine is clinically appropriate:

• follow the BNF and the SmPC for prescribing and monitoring information
• prescribe the formulation with the lowest acquisition cost (see the BNF and PrescQIPP)unless specific patient factors require an another formulation.

Liothyronine for depression

Treatment of depression should follow the NICE guideline Depression in adults: treatment and management.

Where liothyronine is prescribed for the treatment of depression only, this should be under the advice of an NHS consultant psychiatrist.

Where liothyronine is prescribed for the treatment of depression in patients with suspected or established thyroid disease, this should be under the advice of an NHS consultant psychiatrist and NHS consultant endocrinologist.

Patients currently prescribed liothyronine

Patients who have already had a review by an NHS consultant psychiatrist should continue to be prescribed liothyronine under existing arrangements.

Patients who have not already had a review and are established on liothyronine should have a review by an NHS consultant psychiatrist.

If after completion of a 3 month or longer review by an NHS consultant psychiatrist the decision is to continue liothyronine, primary care repeat prescribing would be reasonable in line with any local shared care arrangements (Responsibility for prescribing between primary and secondary/tertiary care and Shared care for medicines guidance, a standard approach).

When liothyronine is clinically appropriate, prescribe the formulation with the lowest acquisition cost (see the BNF and PrescQIPP)unless specific patient factors require another formulation.

Prescribing liothyronine for depression is off-label use. Healthcare professionals should follow relevant professional guidance. They should take full responsibility for the decision when prescribing or advising the use of off-label or unlicensed medicines. This includes considering the contraindications, warnings, monitoring requirements and other safety recommendations for the medicine. More information on this can be found at:

• General Medical Council’s prescribing guidance: prescribing unlicensed medicines
• Medicines and Healthcare products Regulatory Agency’s drug safety update for off-label or unlicensed use of medicines.
• NHS medicines information.

New patients

Liothyronine as monotherapy or in combination with levothyroxine should only be initiated by an NHS consultant psychiatrist.

Liothyronine for thyroid cancer

Liothyronine is recommended as part of the management of thyroid cancer in preparation for radioiodine remnant ablation (RRA), radioiodine therapy (I¹³¹) or in preparation for a sestamibi parathyroid scan.

• Prescribing and related responsibilities should remain with the specialist as this is for short-term use.
• Not suitable for continuation in primary care.
• Thyroid cancer patients who have completed their treatment may need to take levothyroxine for life. This should be managed in the same way as for patients with hypothyroidism.

Service provision

The review of NHS patients prescribed liothyronine by an NHS consultant is to be managed locally and scheduled according to service capacity.

Shared care arrangements should be agreed and authorised by the local commissioner.

Patients who are currently obtaining supplies by private prescription or self-funding should be aware of the Guidance for NHS patients who wish to pay for additional private treatment. Patients who have been seen privately can be referred back to the private service for private prescription if this is appropriate.

Products not recommended for prescribing

The prescribing of unlicensed liothyronine and thyroid extract products (e.g. Armour thyroid and ERFA Thyroid) is not recommended as the safety, quality and efficacy of these products cannot be assured:

• compounded thyroid hormones
• iodine containing preparations
• dietary supplementation.

Publication reference: PRN00158