Levothyrox: the new formula put out of action after investigation of the ANSM

Published on 04/13/2024 09:22

As promised for several weeks, the ANSM published this Wednesday, October 11 the first results of its investigation relating to the thousands of reports of side effects attributed to the new formula of Levothyrox. Result? RAS

"... no adverse effects of a new type, which would be specific to the only new formula, have been found. This is, in a nutshell, the first conclusion of the emergency investigation conducted by the ANSM (National Agency for the Safety of Medicines and Health Products) in recent weeks, following thousands of reports of patients treated in Levothyrox.

Nearly 15,000 reports in 6 months

Migraines, vertigo, hair loss, intense fatigue, muscular and articular disorders ... A total of 14633 reports of more or less serious side effects have been reported over the last 6 months by regional pharmacovigilance centers (RPCs), "allowing analysis of 5062 cases "considered serious, with" consequences on family, professional or social life, "said a statement from the agency.

A so-called "unpublished" number that accounts for 0.59% of the 2.6 million patients treated with the new formula Levothyrox , 90.7% of whom turn out to be women , according to the report. investigation.

Thyroid imbalance due to the transition from the old to the new formula

The cause of its inconvenience according to the patients? The new formula of Levothyrox marketed by Merck laboratories since March 2017 and one of the excipients, lactose, was replaced by citric acid and mannitol -on request of the ANSM- to ensure a better stability of the product.

On the side of the health authorities, after analyzing these data, if "the survey confirms the occurrence of thyroid imbalances for some patients during the transition from Levothyrox old formula to Levothyrox new formula", they are neither new nor related to new components in themselves of the drug but to a "thyroid imbalance in connection with the change of treatment". And the ANSM to specify: "Indeed, any change of specialty or formula can change the hormonal balance and require a readjustment of the dosage that may require some delay. "

Nevertheless, the collection and recording of the reports continues and will be "the subject of subsequent publications" indicates the technical committee in charge of the investigation which also proposes the creation of an ad hoc multidisciplinary group to discuss "the frequency unexpected reports and especially the presence of identical clinical signs in patients, whether in hypo-or hyperthyroidism confirmed by TSH values or with TSH in the expected standards ".

L-Thyroxin Henning, a treatment alternative available October 16

Recognizing a "lack of information" patients, the Minister of Health Agnès Buzyn had announced the temporary return of the old formula of Levothyrox, the Euthyrox "reserved for patients who could not get used to the new version »October 2 in pharmacy. Problem, extremely limited stocks from abroad - or just a few boxes per pharmacy - reported since by patients whose anger does not fall.

In parallel, and as desired by the Minister, a diversification of the treatment offer is underway.
Thus, from Monday, October 16, 2017, the L-Thyroxin Henning, 'marketed for several years in Germany by the Sanofi laboratory, will be available in a sustainable way for patients treated for thyroid disorders and especially those with adverse effects persistent with Levothyrox (new formula). ", Says the ANSM on its website.

Currently, in France, only L-Thyroxine Serb in oral drops solution is proposed, primarily to children, in addition to Levothyrox.