Lipitor, also known as atorvastatin, is a medication commonly prescribed to lower cholesterol levels and reduce the risk of heart disease. While it is generally well-tolerated, like any medication, it can cause side effects. Most side effects associated with Lipitor are mild and temporary, but there are some unusual or rare side effects that have been reported.

According to the sources provided, here are some of the unusual or rare side effects that may occur with Lipitor:

1. Muscle-related side effects: Lipitor can cause muscle pain, weakness, or tenderness. In rare cases, it may lead to a serious condition called rhabdomyolysis, which can cause muscle breakdown and kidney damage [2].

2. Liver problems: Lipitor may cause liver damage, although this is rare. Symptoms of liver problems include yellowing of the skin or eyes, dark urine, and persistent nausea or vomiting [2].

3. Allergic reactions: While rare, some individuals may experience allergic reactions to Lipitor. Signs of an allergic reaction may include rash, itching, swelling, severe dizziness, or trouble breathing [3].

4. Neurological side effects: In rare cases, Lipitor may cause memory loss, confusion, or other cognitive problems. These side effects are usually mild and reversible upon discontinuation of the medication [3].

5. Blood sugar changes: Lipitor may affect blood sugar levels, causing an increase in blood sugar. This is more likely to occur in individuals with diabetes or those at risk of developing diabetes [1].

It is important to note that the occurrence of these unusual or rare side effects is relatively low. Most individuals taking Lipitor do not experience any of these side effects. If you are concerned about any potential side effects, it is recommended to consult with your healthcare provider.

In summary, while Lipitor is generally well-tolerated, it can cause some unusual or rare side effects. These may include muscle-related side effects, liver problems, allergic reactions, neurological side effects, and blood sugar changes. It is important to be aware of these potential side effects and consult with a healthcare provider if you have any concerns.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.mayoclinic.org/drugs-supplements/atorvastatin-oral-route/side-effects/drg-20067003
[3] https://www.medicalnewstoday.com/articles/drugs-lipitor-side-effects