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  1. Postmarket Drug Safety Information for Patients and Providers

Levothyroxine Sodium Product Information


In 2007, the Food and Drug Administration (FDA) issued letters to all new drug application (NDA) and abbreviated new drug application (ANDA) holders requiring that they change the specifications for their products so that all levothyroxine sodium products approved for use in humans will meet a 95% to 105% potency specification throughout their labeled shelf-lives.

This action was part of the agency’s ongoing efforts to address concerns about the variability in the stability profile of FDA approved levothyroxine sodium products and is consistent with FDA’s previous regulatory actions intended to ensure that levothyroxine sodium drug products maintain their quality throughout their shelf lives.

Related Information

For the following resources, please see the FDA Archive

  • Questions and Answers on Levothyroxine Sodium Products
  • Sample Letter to NDA and ANDA Holders of Levothyroxine Sodium products
  • Levothyroxine letter to USP
  • Public Meeting for Levothyroxine Sodium Therapeutic Equivalence May 23, 2005, Washington, DC
  • 2006 Endocrinologic and Metabolic Drugs Advisory Committee
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