Lipitor is a medication that is used to lower cholesterol levels in the blood. According to the information provided by the sources [1][2], the duration of Lipitor treatment depends on the individual's condition. It is generally prescribed for a long-term period, and the treatment can be continued as long as it is effective and the patient tolerates it well. The dosage and duration of treatment are usually determined by a doctor based on the patient's medical history, cholesterol levels, and other factors.

It is recommended to take Lipitor at the same time every day, preferably at night, as it is believed to be more effective in reducing cholesterol levels during the night [3]. However, it is important to follow the doctor's instructions regarding the timing of the medication.

In conclusion, the duration of Lipitor treatment varies depending on the individual's condition and is usually prescribed for a long-term period. It is important to take Lipitor at the same time every day, preferably at night, to ensure its effectiveness. It is recommended to follow the doctor's instructions regarding the dosage and duration of treatment.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.nhs.uk/medicines/atorvastatin/how-and-when-to-take-atorvastatin/
[3] https://www.drugs.com/medical-answers/does-lipitor-work-better-if-you-take-it-at-night-416127/