After reviewing the sources provided, there is no direct evidence to suggest that Lipitor, a medication used to lower cholesterol levels, affects flexibility in yoga practice. Lipitor's active ingredient is atorvastatin, which works by inhibiting an enzyme that produces cholesterol in the liver [1]. The medication has been shown to be effective in reducing cholesterol levels and lowering the risk of heart disease [2].

The study published in the National Library of Medicine found that yoga can improve flexibility and balance in older adults [3]. The study did not mention any potential interactions between yoga and Lipitor.

Another article from EurekAlert discusses the benefits of yoga for individuals with high cholesterol. The article mentions that yoga can help reduce stress and inflammation, which are both risk factors for heart disease [4]. However, the article does not mention any negative effects of combining yoga and Lipitor.

In summary, while Lipitor has been shown to be effective in reducing cholesterol levels, there is no direct evidence to suggest that it affects flexibility in yoga practice. It is always recommended to consult with a healthcare provider before starting any new medication or exercise routine.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3463373/
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3463373/
[4] https://www.eurekalert.org/news-releases/922992