Lipitor, also known as atorvastatin, is a medication used to lower cholesterol levels in the blood. While it is generally well-tolerated, it can have some side effects. According to the NHS [2], the most common side effects of atorvastatin include headache, nausea, diarrhea, constipation, and stomach pain. In addition, muscle aches and pains are also common, and can sometimes be severe. In rare cases, atorvastatin can cause liver problems, which may lead to jaundice, dark urine, and abdominal pain. Patients taking atorvastatin should also be aware of the potential for an allergic reaction, which can cause hives, swelling, and difficulty breathing.

Drugwatch [3] notes that while the side effects of atorvastatin are generally mild, they can be serious in some cases. For example, severe muscle pain or weakness can be a sign of a rare but serious condition called rhabdomyolysis, which can lead to kidney damage or failure. Patients taking atorvastatin should also be aware of the potential for drug interactions, as the medication can interact with other drugs and supplements.

Overall, while Lipitor is generally well-tolerated, it can have some side effects, particularly related to muscle pain and liver problems. Patients taking atorvastatin should be aware of these potential side effects and should talk to their doctor if they experience any symptoms.

Sources:
[2] https://www.nhs.uk/medicines/atorvastatin/side-effects-of-atorvastatin/
[3] https://www.drugwatch.com/lipitor/side-effects/