The revelation of a CNRS researcher should revive the controversy around Levothyrox. The new formulaof this drug indicated for thyroid disorders was questioned after complaints from 31,000 patients ofunwanted effects(headache, fatigue, muscle pain, depression, hair loss). For Jean-Christophe Garrigues, researcher at the Laboratory of molecular interactions and chemical and photochemical reactivity (IMRCP) at the University of Paul Sabatier in Toulouse (CNRS), a chemical element could be at the origin of the problem. On the Media sites (paid access article), the expert claims to have detected a significant peak of impurities in the Levothyrox formula put on the market in March 2017.
Last July, the scientist began to analyze the synthesis of research on the composition of a Levothyrox tablet. Its work is carried out at the request of the French Association of Thyroid Patients (AFMT). By decorticating this chromatogram (analysis of the chemical constituents of a mixture), the researcher points to the presence of this “impure” chemical element in the controversial Levothyrox formula. These chemical elements are absent from the old formula and would be present in less quantity in the tablets currently sold in pharmacies.
The CNRS researcher must present his work to the AFMT.
The ANSM ensures the “good quality of the new formula”
For its part, the national drug safety agency (ANSM) has cracked a communicated Thursday, October 4which calls into question the “interpretation” of the CNRS researcher. “The chromatographic analyzes carried out for the detection of dextrothyroxine show the presence of amounts of levothyroxine comparable between the old and the new formula, which is therefore not under-dosed. They also show the presence of dextrothyroxine only in trace amounts in the new as well as in the old formula, which is fully in line with the expected specifications. The ANSM is also wondering about the method used by the CNRS researcher. “These chromatograms only identify the presence of dextrothyroxine and levothyroxine and cannot generate any other interpretation.” It ensures that “all the checks carried out in the ANSM laboratories have confirmed the good quality of the new Levothyrox formula”.
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