After reviewing the available information, there is no specific evidence to suggest that Lipitor dosage is different for competitive swimmers.

Lipitor, also known as atorvastatin, is a medication used to treat high cholesterol levels and prevent cardiovascular disease [1]. The dosage for Lipitor is typically determined by a patient's medical history, current health status, and response to treatment [1].

In a study examining the effects of atorvastatin on muscle damage in swimmers, the medication was administered at a dosage of 8 mg per day [2]. However, this study did not investigate whether a different dosage would be appropriate for competitive swimmers specifically.

Furthermore, a master's thesis exploring the relationship between atorvastatin and muscle damage in swimmers did not mention any variations in dosage for competitive swimmers [3].

In summary, while there is some research on the use of atorvastatin in swimmers, there is no evidence to suggest that the dosage for Lipitor is different for competitive swimmers. It is important to consult with a healthcare professional for personalized medical advice.

Sources:
[1] <https://www.drugpatentwatch.com/p/tradename/LIPITOR>
[2] <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6341496/>
[3] <https://aquila.usm.edu/cgi/viewcontent.cgi?article=1722&context=masters_theses>