Lipitor is a brand name for the drug atorvastatin, which is a statin used to lower cholesterol levels in the blood. According to DrugPatentWatch [1], Lipitor is one of the most widely prescribed drugs in the world, with over 125 million prescriptions filled in the United States alone.

While statins are generally well-tolerated, they can cause muscle-related adverse events in some patients. According to a study published in the Journal of Clinical Medicine [2], muscle-related adverse events are the most common side effect of statins, with an incidence rate of up to 10%. These adverse events can range from mild muscle pain to severe muscle damage (rhabdomyolysis).

UpToDate [3] notes that muscle-related adverse events are more common in patients taking higher doses of statins, in patients with a history of muscle-related adverse events, and in patients taking certain other medications. However, the risk of muscle-related adverse events is still relatively low, and the benefits of statin therapy in reducing the risk of cardiovascular events generally outweigh the risks.

In summary, while muscle-related adverse events are a known side effect of statins like Lipitor, they are relatively uncommon and occur in up to 10% of patients. The risk of muscle-related adverse events can be increased in certain patient populations, but the benefits of statin therapy generally outweigh the risks.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4972163/
[3] https://www.uptodate.com/contents/statin-muscle-related-adverse-events