Lipitor is a medication that contains atorvastatin, which is a type of drug called a statin. Statins are used to lower cholesterol levels in the blood, which can help prevent heart disease and stroke. Before restarting Lipitor, it is important to talk to your doctor about any potential risks and precautions.

According to the drug label [3], Lipitor should not be taken by people who have liver problems or are pregnant or breastfeeding. Additionally, people who are allergic to atorvastatin or any of the other ingredients in Lipitor should not take this medication.

The BMJ [2] article suggests that people who have experienced muscle pain or weakness while taking Lipitor in the past should talk to their doctor before restarting the medication. This is because muscle problems are a known side effect of statins, and in rare cases, they can lead to a serious condition called rhabdomyolysis.

Drug Patent Watch [1] provides information on the expiration of Lipitor's patent, but does not offer specific precautions for restarting the medication.

In summary, before restarting Lipitor, it is important to discuss any potential risks and precautions with your doctor. People with liver problems, allergies to atorvastatin, or who are pregnant or breastfeeding should not take Lipitor. Those who have experienced muscle pain or weakness while taking Lipitor in the past should also talk to their doctor.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.bmj.com/content/353/bmj.i3305
[3] https://www.accessdata.fda.gov/drugsatfda_docs/label/2019/020702s073lbl.pdf