Switching between generic levothyroxine products does not make a marked clinical difference, suggests a new study published in JAMA Internal Medicine.

A comparative effectiveness research study included 15,829 patients and noted that people who switched their generic levothyroxine product did not experience any change in serum thyrotropin (TSH) levels, when compared with those who continued taking the same product.

In a comparison of the lab results 6 weeks to 12 months following the index date, the proportion having normal TSH levels (0.3-4.4 mIU/L) was not different between the group that switched the generic levothyroxine product and those who did not switch the product (84.5% vs. 82.7%). Around 3.1% of those who did not switch had considerably abnormal TSH levels (<0.1 mIU/L or >10 mIU/L) compared to 2.5% of those who switched the levothyroxine product. The investigators did not see any between-group differences in the proportion with abnormal TSH levels. Average TSH levels were same, at 2.7 mIU/L, in both the groups… (Medpage Today)