Nearly 3 million French people take this drug, it can damage bones

It is the third most prescribed medication in France, according to figures published by Health Insurance in November. Nearly 32 million boxes are delivered to pharmacies each year to 2.8 million French people aged 67 on average. But be careful. A study by Johns Hopkins University researchers presented next week at the annual meeting of the Radiological Society of North America (RSNA) highlights a “concerning” side effect. “A risk and benefit assessment must be carried out, taking into account the need for the treatment and its possible adverse effects” estimates Dr. Jennifer Mammen, endocrinologist and co-author of the study.

Dr. Shadpour Demehri, radiologist and co-senior author, emphasizes monitoring thyroid functions. For good reason, the famous drug is commonly prescribed to treat hypothyroidism. In people with hypothyroidism, the thyroid gland does not produce enough thyroxine on its own, often leading to fatigue, weight gain, and hair loss. This thyroid problem can lead to serious complications and must be taken care of. But the researchers demonstrate here that the main drug to treat this thyroid disorder, levothyroxine (marketed in particular under the name Levothyrox® in France) can be linked to bone loss in the elderly.

Their study was conducted on participants aged 65 and over who all had normal thyroid function. Over a 6-year period, researchers compared 81 levothyroxine users to 364 non-users. The results showed that levothyroxine use was associated with greater loss of total bone mass and bone density, even in participants whose TSH levels were within the normal range. “Our study suggests that even following current guidelines, levothyroxine use appears to be associated with greater bone loss in older adults”commented Dr. Demehri on the RSNA website.

This reduction in bone mass could increase the risk of fractures, which is already a concern among seniors. For older adults, this research reinforces the need for increased monitoring, particularly in cases where levothyroxine has been prescribed for many years without reevaluation. The researchers believe that they must regularly discuss their treatment with the prescribing doctor.