The FDA's MedWatch program compiles a quarterly report of important changes to safety labeling for boxed warnings for drugs and therapeutic biologics.
Boxed warnings highlight:
Adverse reactions so serious in proportion to the potential benefit from the drug that it is essential that it be considered in assessing the risks and benefits of using the drug; OR
Serious adverse reactions that can be prevented/reduced in frequency or severity by appropriate use of the drug; OR
FDA approved the drug with restrictions to ensure safe use because FDA concluded that the drug can be safely used only if distribution or use is restricted.
Label changes are searchable in the Drug Safety Labeling Changes (SLC) database.
Levothyroxine sodium (Levo-T®)
For more on this Drug Safety Labeling Change, click here.
For full prescribing information, click here.

Updated Boxed Warning
WARNING: NOT FOR TREATMENT OF OBESITY OR FOR WEIGHT LOSS
Thyroid hormones, including Levo-T, either alone or with other therapeutic agents, should not be used for the treatment of obesity or for weight loss.
In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction.
Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects.
Public Information from the FDA and Medscape
Information provided by FDA and/or its employees on this website is for educational purposes only, and does not constitute medical advice. Any statement or advice given by an FDA employee on this website does not represent the formal position of FDA. FDA and/or any FDA employee will not be liable for injury or other damages resulting to any individuals who view FDA-related materials on this website.
Cite this: Drug Safety Warnings and Updates: October-December 2017 - Medscape - Feb 16, 2018.