The French Medicines Agency (ANSM) announced on Wednesday that the Euthyrox treatment, identical to the old formula (Levothyrox) prescribed for thyroid diseases, will continue to be distributed "until the end of 2028" in France.
"The Merck laboratory has indicated to health authorities its ability to extend the supply of Euthyrox until the end of 2028 in France," according to a statement from the health agency.
The distribution of Euthyrox, imported from Germany since the end of 2017, was initially due to stop in 2020 in France but it has already been extended several times against the backdrop of a legal battle over this new formula, which uses the same active ingredient, levothyroxine, but with new excipients.
"This extension of supplies allows us to continue supporting patients still being treated with Euthyrox towards another levothyroxine-based medication," emphasizes the ANSM.
The various specialties containing this same hormone, which are available in France with their different compositions (excipients), have also been marketed abroad for several years, recalls the drug watchdog.
"The reported adverse effects can have different causes, including the fact that the dose needs to be adjusted to the patient," the agency points out in a practical guide for patients and doctors to ensure a safe transition, reminding them that this "rebalancing can take between a few weeks and several months."
It recommends that doctors no longer initiate treatment with Eurothyrox in view of the definitive cessation of marketing.
Taking synthetic thyroid hormones, such as levothyroxine, helps to compensate for the lack of hormone production by the thyroid.
The ANSM (French National Agency for Medicines and Health Products Safety) was formally charged in December 2022 with "deception," and then again in 2024 with "aggravated deception," a similar case already targeting the German pharmaceutical group Merck. Following confirmation of these charges, both the agency and the laboratory filed an appeal with the Court of Cassation.
The case began in 2017 with the arrival on the French market of a new formula of Levothyrox, then used daily by more than two million patients in France. This formula contained the same active ingredient, levothyroxine, but with new excipients.
More than 30,000 patients then complained of side effects (headaches, insomnia, dizziness, etc.).
Health authorities, starting with the ANSM, initially rejected the idea of a mechanism directly induced by the new formula, before concluding that the change had not caused any "serious" health problems.
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