Levothyroxine (L-thyroxine, T4). Skutki uboczne - ciekawostka

In an unprecedented U-turn, the French government has asked drug manufacturer Merck to return to the market a thyroid hormone replacement drug named Levothyrox that the company had phased out and replaced with a new formulation just 6 months ago. The move, which overturns a decision by France's National Agency for Medicines and Health Products Safety (ANSM), comes after thousands of patients complained about side effects from the new drug, creating a media storm and a political problem for the French government.

About 3 million French people, 80% of them women, take Levothyrox, which replaces the hormone thyroxine in patients with hypothyroidism. Among their complaints over the past few months: hair loss, weight gain, extreme fatigue, headaches, diarrhea, and heightened heart rates....
But their problems are a bit of a medical mystery, because Merck hasn't changed the active ingredient in Levothyrox; what's new are the excipients, ingredients that help stabilize and bulk up the drug. And some experts say the scare has less to do with pharmacology than with consumer distrust, poor communication, and media pressure.

Merck introduced the new Levothyrox formulation in March, at the request of ANSM, which said there was too much variation in the amount of active ingredient over the drug's shelf life and between individual tablets. The new version contains mannitol and citric acid—both innocuous and widely used as excipients—instead of lactose
http://www.sciencemag.org/news/2017/09/france-brings-back-phased-out-drug-after-patients-rebel-against-its-replacement

But in France, the backlash has been intense. Patients began reporting side effects in June; as dramatic stories appeared in the press, a petition asking for a return to the old formulation gathered nearly 300,000 signatures and some 9000 reports of adverse events poured into ANSM's website. A dedicated telephone line received more than 150,000 calls in the first week.

Rumors started flying as well. Patients accused Merck, which has a monopoly on thyroxine replacement treatments in France, of trying to boost profits by making the new drug on the cheap in China