Lipitor, also known as atorvastatin, is a medication used to lower cholesterol levels in the blood. It is a type of drug called a statin, which works by blocking the enzyme that produces cholesterol in the liver [3]. According to Drug Patent Watch [1], the patent for Lipitor expired in 2011, which means that the drug is now available as a generic medication.

Statins like Lipitor are typically prescribed to people who have high levels of LDL cholesterol, also known as "bad" cholesterol, in their blood. According to the British Heart Foundation [2], statins are usually prescribed for people who have a 10% or higher risk of developing cardiovascular disease within the next 10 years. However, statins may also be prescribed to people who have other risk factors for heart disease, such as diabetes or high blood pressure.

Lipitor and other statins are typically taken once a day, usually at night, because the liver produces more cholesterol at night than during the day [3]. It may take several weeks or even months for the full effects of the medication to be seen, so it is important to continue taking the medication as prescribed by a doctor. Cholesterol levels should be checked regularly while taking Lipitor to ensure that the medication is working effectively.

In conclusion, Lipitor works by blocking the enzyme that produces cholesterol in the liver and is typically prescribed to people who have high levels of LDL cholesterol in their blood. It may take several weeks or months for the full effects of the medication to be seen, and cholesterol levels should be checked regularly while taking Lipitor. The patent for Lipitor expired in 2011, and it is now available as a generic medication.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.bhf.org.uk/informationsupport/heart-matters-magazine/medical/drug-cabinet/statins
[3] https://my.clevelandclinic.org/health/treatments/22282-statins