Lipitor is a brand name for the drug atorvastatin, which is used to lower cholesterol levels in the blood. According to the sources provided, the frequency of taking Lipitor depends on the prescribed dosage and the patient's condition.

The first source, Drug Patent Watch [1], provides information on the patent expiration of Lipitor but does not offer details on how often the medication should be taken.

The second source, GoodRx [2], explains that the typical starting dose of atorvastatin is 10-20 mg once a day, with the maximum dose being 80 mg per day. However, the actual frequency of taking the medication depends on the patient's individual needs and the instructions of their healthcare provider.

The third source, NHS [3], provides more specific information on how and when to take atorvastatin. It advises taking the medication once a day, preferably in the evening, with or without food. The tablet should be swallowed whole with water and not crushed or chewed. The NHS also notes that it may take up to four weeks for the medication to start lowering cholesterol levels, and that patients should continue taking it even if they feel well.

In summary, the frequency of taking Lipitor (atorvastatin) depends on the prescribed dosage and the patient's individual needs. Typically, it is taken once a day, preferably in the evening, with or without food [2][3]. Patients should follow the instructions of their healthcare provider and continue taking the medication even if they feel well [3].

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.goodrx.com/atorvastatin/what-is
[3] https://www.nhs.uk/medicines/atorvastatin/how-and-when-to-take-atorvastatin/