Lipitor (atorvastatin) is a medication used to treat high cholesterol levels in the blood. According to the American Academy of Family Physicians [2], the starting dose for Lipitor is 10-20 mg/day, and the maximum dose is 80 mg/day. However, the dose may need to be adjusted for patients taking other medications.

DrugPatentWatch [1] explains that some medications may increase the levels of Lipitor in the blood, leading to an increased risk of side effects. These medications include cyclosporine, clarithromycin, itraconazole, and HIV protease inhibitors. In these cases, the maximum recommended dose of Lipitor is 20 mg/day.

On the other hand, the COVID-19 Treatment Guidelines [3] warn that certain medications may decrease the levels of Lipitor in the blood, reducing its effectiveness. These medications include rifampin, St. John's Wort, and some HIV medications. In these cases, the dose of Lipitor may need to be increased to achieve the desired effect.

It is important to consult with a healthcare provider before making any changes to the dose of Lipitor or any other medication. They can provide guidance on the appropriate dosage adjustments based on individual patient needs and medical history.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.aafp.org/pubs/afp/issues/2007/0515/p1487.html
[3] https://www.covid19treatmentguidelines.nih.gov/therapies/antivirals-including-antibody-products/ritonavir-boosted-nirmatrelvir--paxlovid-/paxlovid-drug-drug-interactions/