According to the sources provided, it is recommended to take Lipitor (atorvastatin) at night. Lipitor is a medication used to lower cholesterol levels in the blood and reduce the risk of heart disease [1]. Studies have shown that taking Lipitor at night can be more effective in reducing cholesterol levels than taking it in the morning [2]. The NHS recommends taking Lipitor at night, as this is when the body produces more cholesterol [3]. However, it is important to follow the specific instructions provided by your doctor or pharmacist, as they may differ depending on your individual circumstances. It is also important to note that Lipitor should be taken regularly, at the same time each day, to ensure maximum effectiveness.

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