Lipitor, also known as atorvastatin, is a medication used to lower cholesterol levels in the blood. According to the sources provided, stopping the use of Lipitor can improve liver function, but the exact timeframe for this improvement is not specified.

The first source, Drug Patent Watch [1], provides information about the drug Lipitor and its patent status. It does not provide any information about how long it takes for liver function to improve after stopping Lipitor.

The second source, a book chapter from the National Center for Biotechnology Information [2], discusses the potential side effects of statins, including Lipitor. It states that statins can cause liver damage, but this is rare and typically reversible upon discontinuation of the medication. However, the chapter does not provide a specific timeline for liver function improvement after stopping Lipitor.

The third source, Mayo Clinic [3], also discusses the potential side effects of statins, including liver damage. It states that liver function tests should be monitored regularly while taking statins and that liver damage is typically reversible upon discontinuation of the medication. However, it does not provide a specific timeline for liver function improvement after stopping Lipitor.

In summary, while the sources suggest that stopping Lipitor can lead to improved liver function, none of them provide a specific timeline for this improvement. It is important to consult with a healthcare provider for personalized advice on medication use and potential side effects.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ncbi.nlm.nih.gov/books/NBK548236/
[3] https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/statin-side-effects/art-20046013