Lipitor, also known as atorvastatin, is a medication that is commonly used to lower cholesterol levels in the blood. According to [1], the most common adverse effects of Lipitor are muscle pain, weakness, and inflammation, which can lead to rhabdomyolysis, a serious condition that can cause kidney damage. Other side effects that may occur include headache, nausea, diarrhea, and constipation.

The Mayo Clinic [2] lists additional side effects that can occur with statins, including liver damage, memory loss, confusion, and high blood sugar. However, these side effects are rare and typically occur in individuals who are taking high doses of statins or who have pre-existing conditions that increase their risk.

The NHS [3] also lists muscle pain and weakness as the most common side effects of atorvastatin, along with stomach pain, indigestion, and a rash. However, it notes that these side effects are usually mild and go away on their own.

It is important to note that not everyone who takes Lipitor will experience side effects, and the benefits of the medication in reducing the risk of heart attack and stroke generally outweigh the risks. However, individuals who experience severe or persistent side effects should speak with their healthcare provider.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/statin-side-effects/art-20046013
[3] https://www.nhs.uk/medicines/atorvastatin/side-effects-of-atorvastatin/