Lipitor, also known as atorvastatin, is a medication used to lower cholesterol levels in the blood. According to the Drug Patent Watch [1], Lipitor works by inhibiting the enzyme HMG-CoA reductase, which is responsible for producing cholesterol in the liver. By doing so, Lipitor reduces the amount of cholesterol that is produced in the body and helps to lower cholesterol levels in the blood.

However, there are some potential side effects of Lipitor, including muscle pain and weakness. A study published in the Journal of Clinical and Diagnostic Research [2] found that statins, including Lipitor, can cause muscle damage in some patients. The study suggests that the muscle damage may be due to the inhibition of CoQ10, a substance that is important for muscle function. The study also suggests that the risk of muscle damage may be higher in patients who are taking higher doses of statins or who are taking multiple medications.

The Mayo Clinic [3] also notes that muscle pain and weakness are common side effects of statins, including Lipitor. The Mayo Clinic recommends that patients who experience muscle pain or weakness while taking Lipitor should contact their doctor immediately.

In conclusion, Lipitor works by inhibiting the enzyme responsible for producing cholesterol in the liver, which helps to lower cholesterol levels in the blood. However, Lipitor can also cause muscle pain and weakness in some patients. This may be due to the inhibition of CoQ10, a substance that is important for muscle function. Patients who experience muscle pain or weakness while taking Lipitor should contact their doctor immediately.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2949584/
[3] https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/statin-side-effects/art-20046013