Lipitor is a brand name for the drug atorvastatin, which is a type of medication called a statin that is used to lower cholesterol levels in the blood. While it is generally considered safe and effective, there are potential side effects associated with its use.

According to the Mayo Clinic [2], some of the most common side effects of atorvastatin include:

- Muscle pain and damage: This is the most common side effect, and can range from mild discomfort to severe muscle damage that can lead to kidney failure. Symptoms can include weakness, tenderness, or pain in the muscles, especially if accompanied by fever or dark urine. Patients should report any unexplained muscle pain or weakness to their doctor immediately.
- Liver damage: In rare cases, atorvastatin can cause liver damage, which can be indicated by yellowing of the skin or eyes, dark urine, or persistent nausea and vomiting. Patients should report any symptoms of liver problems to their doctor immediately.
- Digestive problems: Atorvastatin can cause digestive problems such as constipation, diarrhea, nausea, or stomach pain. These symptoms are usually mild and go away on their own, but patients should talk to their doctor if they persist or are severe.
- Increased blood sugar: Atorvastatin can sometimes increase blood sugar levels, which can be a concern for patients with diabetes or those at risk for developing diabetes. Patients should monitor their blood sugar levels closely while taking atorvastatin.

Other potential side effects of atorvastatin, as listed by the NHS [3], include:

- Headache
- Dizziness
- Insomnia
- Rash or itching
- Joint pain
- Memory loss or confusion (although this is rare)

It's important to note that not everyone will experience side effects from atorvastatin, and many people take the medication without any problems. However, patients should be aware of the potential risks and talk to their doctor if they have any concerns.

Sources:
[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/
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR