Adverse effects reported since the arrival of the new Levothyrox are due to “an imbalance of the thyroid” caused by the change of treatment, and not to the new formula itself, according to the first results of the survey of pharmacovigilance published on Wednesday 11 October 2017 by the Agency of the medicine MAN. “All adverse events testify an imbalance in the thyroid in connection with the change of treatment; no adverse effect of a new type, which would be specific to the single new formula has not yet been found,” says the MAN in a press release. “Any change of specialty or formula can alter the hormonal balance and may require a readjustment of the dosage” which can take “a certain period”, continues the Agency.
The reports continue
On September 15, “14.633 reports have been received by the regional centres of pharmacovigilance (CRPV),” according to the MSNA. “Of this total, cases were reported by patients as severe, it is reported as having repercussions on family life, professional or social, and the most documented, 5.062 cases, were able to be saved as a priority in the base nationale de pharmacovigilance (BNPV),” she continued. On these 5.062 cases, four deaths, but “the link with Levothyrox is not established”, it is noted in the report of the survey, put online on the site of the MSNA.
“The collection of notifications and registration in the BNPV is ongoing and will be the subject of subsequent publications,” says the MAN, stressing that “the 14.633 reports (…) represent 0.6% of the 2.6 million patients treated with Levothyrox new formula”. “The number of reports of adverse effects with Levothyrox new formula is totally new, with a possible booster effect of the portal-reporting and social networks,” notes the report. The effects most frequently reported are fatigue, headaches, insomnia, dizziness, joint and muscle pain and hair loss. The 5,062 cases analyzed dealt with 90.7% of women (compared to 9.3% of men).
The report looks into the cases of “some of the patients who exhibit both signs of hypo or hyperthyroidism”. This is one of the reasons for which its authors hope “that the establishment of a working group consisting of health professionals, pharmacovigilants and patients in order to continue the investigations”. The new formula of the Levothyrox has been claimed by the MAN in the laboratory Merck in 2012 to, according to it, to make the product more stable over time. The change relates not to the active principle, but on other substances, and excipients. Face the wrath of patients reporting side effects, the Health minister Agnès Buzyn had announced on September 15 the return within fifteen days of the old formula before the arrival of alternative medicines.
The old formula is arrival in the pharmacy on October 2, under the name of Euthyrox), but for a length of time and in limited quantities. After this transitional solution, the MSNA announced Wednesday that the L-Thyroxin Henning laboratory (Sanofi), which is intended to offer an alternative to patients who do not support the new Levothyrox, would be available on October 16th (and from 23 in the overseas territories depending on the laboratory). Finally, another drug will be available from November. Until this crisis, Levothyrox was in a situation of quasi-monopoly in France.