Lipitor is a brand name for the drug atorvastatin, which is used to lower cholesterol levels in the body. When taking Lipitor, it is important to be cautious about the use of antacids, as some can interact with the medication and reduce its effectiveness. According to Drugs.com [1], Tums Regular Strength is safe to take with Lipitor, as there are no known interactions between the two drugs. However, it is important to note that other antacids, such as Maalox and Mylanta, may reduce the absorption of Lipitor and should be taken at least two hours before or after taking the medication. Additionally, it is always important to consult with a healthcare provider before taking any new medications or supplements, including antacids, while taking Lipitor [2].

Sources:
[1] https://www.drugs.com/drug-interactions/atorvastatin-with-tums-regular-strength-276-0-464-3778.html
[2] https://www.peacehealth.org/medical-topics/id/hn-1090009