Lipitor is a medication used to lower cholesterol levels in the body. According to the sources provided, the reason for increasing the dosage of Lipitor may vary based on the individual's medical condition and the effectiveness of the medication.

One reason for increasing the dosage of Lipitor could be due to the expiration of its patent. As per Drug Patent Watch [1], the expiration of the patent has led to the availability of generic versions of Lipitor, which has resulted in a decrease in its price. However, the generic versions may not be as effective as the original Lipitor, and some patients may require an increased dosage to achieve the desired cholesterol-lowering effect.

Another reason for increasing the dosage of Lipitor could be due to the patient's medical condition. A study published in the Journal of the American College of Cardiology [3] suggests that patients with diabetes may require a higher dosage of Lipitor to achieve the same cholesterol-lowering effect as non-diabetic patients. The study also suggests that higher doses of Lipitor may be required for patients with familial hypercholesterolemia, a genetic condition that causes high cholesterol levels.

Moreover, a study published in the National Center for Biotechnology Information [2] suggests that increasing the dosage of Lipitor may be necessary for patients who do not achieve the desired cholesterol-lowering effect with the initial dose. The study recommends regular monitoring of cholesterol levels to determine the effectiveness of the medication and adjusting the dosage accordingly.

In conclusion, the reasons for increasing the dosage of Lipitor may vary based on the individual's medical condition and the effectiveness of the medication. It is essential to consult a healthcare provider to determine the appropriate dosage of Lipitor based on the patient's medical history and current condition.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://pubmed.ncbi.nlm.nih.gov/20525997/
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4354082/