Lipitor is a brand name for the drug atorvastatin, which is a medication used to lower cholesterol levels in the blood. While it is an effective drug, it can cause side effects in some people. The severity of these side effects can vary from person to person, and some may experience no side effects at all.

According to the National Health Service (NHS) [2], the most common side effects of atorvastatin are headaches, muscle and joint pain, and nosebleeds. Other possible side effects include digestive problems, such as nausea, diarrhea, and constipation, as well as skin reactions, such as rashes and itching. In rare cases, atorvastatin can cause more serious side effects, such as liver problems, diabetes, and memory loss. However, these side effects are very rare and are usually only seen in people who take the drug for a long time.

Drugwatch [3] states that the most serious side effect of Lipitor is muscle damage, which can lead to a condition called rhabdomyolysis. This condition can cause muscle pain, weakness, and kidney damage. However, this side effect is also rare and is more likely to occur in people who take high doses of the drug or who have other risk factors, such as kidney problems or hypothyroidism.

In summary, while Lipitor can cause side effects, most people experience only mild side effects, such as headaches and muscle pain. Serious side effects are rare and are more likely to occur in people who take high doses of the drug or who have other risk factors. If you experience any side effects while taking Lipitor, you should speak to your doctor, who may be able to adjust your dosage or switch you to a different medication.

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