Lipitor (atorvastatin) is a medication used to lower cholesterol levels in the blood. It is a statin drug that works by inhibiting an enzyme in the liver that produces cholesterol [2]. The dosage of Lipitor should be adjusted based on several factors such as age, gender, liver function, and the presence of other medical conditions.

According to the drug patent watch website, the recommended starting dose of Lipitor is 10-20 mg per day, and the maximum daily dose is 80 mg [1]. However, the dosage may need to be adjusted in certain circumstances. For example, elderly patients may require a lower dose due to a higher risk of side effects [2]. Additionally, patients with liver disease may require a lower dose or may not be able to take Lipitor at all [3].

The Medscape reference also notes that Lipitor dosage should be adjusted when used in combination with other medications that can interact with it, such as certain antibiotics and antifungal drugs. This is because these medications can increase the concentration of Lipitor in the blood, leading to an increased risk of side effects [2].

In summary, Lipitor dosage should be adjusted based on individual patient factors such as age, gender, liver function, and the presence of other medical conditions or medications. It is important to follow the recommended dosing guidelines and consult with a healthcare provider before making any changes to medication dosages [2][3].

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://reference.medscape.com/drug/lipitor-atorvaliq-atorvastatin-342446
[3] https://www.ncbi.nlm.nih.gov/books/NBK430779/