Lipitor is a commonly prescribed medication used to lower cholesterol levels in individuals with high blood cholesterol. It is important to monitor liver function while taking Lipitor, as it can potentially cause liver damage in rare cases. However, the frequency of liver function monitoring may vary depending on individual factors and the healthcare provider's discretion.

According to the Drug Patent Watch website, the prescribing information for Lipitor does not specify a specific frequency for liver function monitoring [1]. However, it is generally recommended to have liver function tests performed before starting Lipitor and periodically thereafter. The frequency of monitoring may be influenced by factors such as the patient's overall health, presence of liver disease or abnormal liver function, and any concurrent medications that may interact with Lipitor.

A study published in the National Center for Biotechnology Information (NCBI) suggests that liver function tests should be conducted before starting statin therapy, including Lipitor, and then repeated at 12 weeks and 6 months after initiating treatment [2]. If liver function tests remain normal at these time points, subsequent monitoring may be done on a yearly basis. However, it is important to note that individual patient characteristics and risk factors should be considered, and more frequent monitoring may be necessary in certain cases.

The Mayo Clinic also recommends monitoring liver function before starting Lipitor and periodically thereafter, particularly during the first few months of treatment [3]. If a patient experiences symptoms such as unexplained fatigue, loss of appetite, abdominal pain, dark urine, or jaundice (yellowing of the skin or eyes), it is important to seek medical attention immediately, as these may be signs of liver damage.

In conclusion, while the specific frequency of liver function monitoring for Lipitor is not explicitly stated in the sources provided, it is generally recommended to have liver function tests performed before starting Lipitor and periodically thereafter. The timing and frequency of monitoring may vary based on individual patient factors and healthcare provider discretion. It is important to follow the guidance of your healthcare provider and report any symptoms of liver damage promptly.

Sources:
[1] Drug Patent Watch: Lipitor. Retrieved from https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] National Center for Biotechnology Information: Statin-associated hepatotoxicity: A review of the literature. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4110821/
[3] Mayo Clinic: Statin side effects: Weigh the benefits and risks. Retrieved from https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/statin-side-effects/art-20046013