Lipitor is a brand name for atorvastatin, a medication used to lower cholesterol levels in the blood. According to the sources provided, Lipitor's dosage instructions vary depending on the patient's condition, age, and other factors.

The recommended starting dose for Lipitor is usually 10 or 20 milligrams (mg) per day, taken once a day, with or without food. The dosage may be increased up to 80 mg per day, depending on the patient's response to the medication and the target cholesterol level.

For patients with homozygous familial hypercholesterolemia, a rare genetic condition that causes high cholesterol levels, the recommended starting dose is 10 or 20 mg per day, taken once a day, with or without food. The dosage may be increased up to 80 mg per day, depending on the patient's response to the medication.

For patients with liver problems, the recommended starting dose is 10 mg per day, taken once a day, with or without food. The dosage may be increased up to 20 mg per day, depending on the patient's response to the medication.

It is important to take Lipitor exactly as prescribed by a healthcare provider. Lipitor should be taken at the same time every day, and it is important not to miss a dose. If a dose is missed, it should be taken as soon as possible, unless it is almost time for the next dose. In that case, the missed dose should be skipped and the regular dosing schedule should be resumed.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.drugs.com/dosage/lipitor.html
[3] https://www.mayoclinic.org/drugs-supplements/atorvastatin-oral-route/proper-use/drg-20067003