If a patient reports persistent symptoms when switching between different 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 in an oral solution formulation.
- levothyroxine is authorised for the control of hypothyroidism. In the UK, prescribing of levothyroxine is usually generic, with no named product specified on the prescription
- patients may thus be changed between different levothyroxine products according to what is available at their local pharmacies, with the prescriber generally unaware of the specific product that the patient is taking at any particular time
- this generic prescribing approach is supported by strict UK regulatory requirements for licensing to ensure compatibility (bioequivalence) between products
- MHRA receives reports of patients experiencing adverse events on switching between different levothyroxine products
- a review has been undertaken and advice has been devised for healthcare professionals below:
Advice for healthcare professionals:
- generic prescribing of levothyroxine remains appropriate for the majority of patients and the licensing of these generic products is supported by bioequivalence testing
- a small proportion of patients treated with levothyroxine report symptoms, often consistent with thyroid dysfunction, when their levothyroxine tablets are changed to a different product – these cases are noted in UK professional guidelines
- if a patient reports symptoms after changing their levothyroxine product, consider testing thyroid function
- if a patient is persistently symptomatic after switching levothyroxine products, whether they are biochemically euthyroid or have evidence of abnormal thyroid function, consider consistently prescribing a specific levothyroxine 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 in an oral solution formulation
- report suspected adverse reactions to levothyroxine medicines, including symptoms after switching products, to the Yellow Card scheme
Reference:
- Drug Safety Update volume 14, issue 10: May 2021: 1.