Levothyroxine brand names
Pro Research Analysisby 
Searched over 200M research papers
Common Levothyroxine Brand Names
Levothyroxine, a medication used to treat hypothyroidism, is available under several brand names worldwide. The most frequently mentioned brands in research and clinical practice include Synthroid, Eltroxin, Thyronorm, Levoxyl (previously Levoxine), Thyrax, and Lethyrox. These brands are widely prescribed and studied in various countries, including the United States, India, Pakistan, and the Netherlands 123578.
Brand Name Differences and Bioequivalence
Synthroid, Eltroxin, Thyronorm, Levoxyl, Thyrax, and Lethyrox
Synthroid is often considered the reference or "parent" brand in many studies, with Eltroxin, Thyronorm, Levoxyl, Thyrax, and Lethyrox being other commonly used brands 123578. Studies have shown that while these brands are all forms of levothyroxine, there can be differences in their physicochemical properties, such as tablet weight, thickness, hardness, and disintegration time. However, these differences generally fall within accepted pharmaceutical standards .
Generic vs. Brand-Name Levothyroxine
Research comparing brand-name and generic levothyroxine products (including Synthroid, Levoxyl, and generics) has found that, according to FDA criteria, most are bioequivalent and can be used interchangeably for the majority of patients 57. However, some studies have noted that switching between brands or between brand-name and generic products can sometimes lead to changes in thyroid hormone levels, requiring dose adjustments in certain patients 14810.
Clinical Implications of Switching Brands
Switching between different levothyroxine brands—such as from Thyronorm or Eltroxin to Lethyrox, or from Thyrax to another brand—has been shown to be safe for most patients, with the majority maintaining normal thyroid-stimulating hormone (TSH) levels after the switch . However, a significant minority may experience changes in TSH levels, and some may require dose adjustments to maintain optimal thyroid function 1810. Clinical experience and research suggest that consistent use of the same brand is preferable, and any switch should be monitored with follow-up TSH testing 1810.
Conclusion
Levothyroxine is available under several brand names, including Synthroid, Eltroxin, Thyronorm, Levoxyl, Thyrax, and Lethyrox. While these brands are generally considered bioequivalent and interchangeable for most patients, small differences exist, and switching brands may require monitoring and possible dose adjustments. Consistency in the brand used is often recommended to ensure stable thyroid hormone levels and avoid unnecessary symptoms or healthcare costs 12357810.
Sources and full results
Most relevant research papers on this topic