Levothyroxine 100mcg tablets made by Teva have been withdrawn from sale in the UK by the MHRA due to concerns about interchangeability of the product with other makes of the drug.

Please see the initial thread regarding suspension here

MHRA suspends licence for Teva evothyroxine

The tablets are marketed in the Teva UK and Numark liveries.

Withdrawal from clinical use:

Teva Levothyroxine 100 microgram Tablets
Numark Levothyroxine 100 microgram Tablets

PL 00289/0039

Dear Colleague,

I am writing to inform you of the suspension of the marketing authorisation for Levothyroxine 100 microgram Tablets manufactured by Teva. The tablets are marketed in the Teva UK and Numark liveries.

This action follows a review by the Commission on Human Medicines (CHM) of manufacturing questions and sporadic reports of potential reduced efficacy with this product. As a precautionary measure, while investigations are continuing, Teva has voluntarily ceased manufacture and distribution of the product, in line with the CHM recommendation.

The CHM review concluded that the Teva product might not be interchangeable with other levothyroxine products, and that no further supplies of the product should be released for marketing until these matters are resolved. Consequently, Teva levothyroxine 100 microgram tablets will cease to be available in the UK within the next few weeks.

Advice for healthcare professionals and patients

  • Prescribers should be alert to the possibility that a change in a patient’s symptoms and TSH status may be attributed to switching between Teva levothyroxine 100 microgram tablets and another product.
  • Most patients are unlikely to notice any difference between the Teva product and another levothyroxine product. However, patients who experience a significant change in symptoms should have their TSH status reviewed and their dose of levothyroxine adjusted accordingly.
  • The following patients may be particularly susceptible to changes in TSH and may require particularly close monitoring:
    • Pregnant women, throughout pregnancy but especially in the first trimester
    • Those with heart disease
    • Those under treatment with TSH suppressive doses of levothyroxine after treatment for thyroid cancer

These patients should be contacted and, if they are taking Teva tablets, be given an early appointment for a clinical review and blood test.

  • After dose adjustment of levothyroxine, consistent with usual practice, TSH should be retested after a period of 6 weeks to confirm blood levels are stabilised within the normal range as determined by their doctor.


A review of Teva levothyroxine 100 microgram tablets was initiated following the receipt of sporadic reports from prescribers and patients raising concerns about the effectiveness of this product. Increased reports in December 2011 and January 2012, including a number that were supported by results of clinical chemistry, showed a loss of control of TSH levels in some patients when switching between Teva levothyroxine tablets and other levothyroxine products.

The MHRA and its independent advisory body, the CHM, considered all available data including: the reported defects; information relating to the manufacturing process; and the results of studies conducted by the MHRA’s Medicines Testing Laboratory. CHM concluded that these data raised uncertainty as to whether Teva's product was interchangeable with other levothyroxine products.

The majority of patients will not incur serious clinical consequences by continuing with their medication and changing to a different levothyroxine product at their next prescription, therefore it is not necessary for them to have an early appointment. However, a loss of control of TSH may pose a risk for certain subgroups of patients—ie, those who are pregnant, especially those in the first trimester of pregnancy, those with heart disease, and those under treatment with TSH suppressive doses of levothyroxine after treatment for thyroid cancer. In light of this it was considered advisable, as a precautionary measure, to suspend the manufacture and distribution of the product.

The suspension will remain in place until the marketing authorisation holder has completed its investigation and resolved the underlying issues.

Further information is available at www.mhra.gov.uk