Lipitor (atorvastatin) is a medication used to lower cholesterol levels in the blood. According to the sources provided [1][2][3], the recommended starting dose of Lipitor for most adults is 10-20 mg once daily. The dosage may be increased up to 80 mg once daily depending on the individual's response to the medication and the severity of their condition. However, the maximum recommended dose is 20 mg daily for patients with severe renal impairment or end-stage renal disease. It is important to follow the dosage instructions provided by the prescribing healthcare provider and to report any side effects or concerns to them promptly. It is also important to note that Lipitor is a prescription medication and should only be taken under the supervision of a healthcare provider.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://reference.medscape.com/drug/lipitor-atorvaliq-atorvastatin-342446
[3] https://www.drugs.com/dosage/lipitor.html