Lipitor, also known as atorvastatin, is a widely prescribed medication used to lower cholesterol levels in the blood. As with any medication, it is important to monitor potential side effects, including liver damage.

According to the drug label provided by DrugPatentWatch [1], liver function tests should be performed before starting Lipitor and periodically thereafter. However, the frequency of monitoring is not specified.

The Harvard Health Blog [2] suggests that liver function tests should be performed before starting Lipitor and then again after 12 weeks. If the results are normal, then the tests can be repeated every six months to a year. However, if there are any concerns about liver function, more frequent monitoring may be necessary.

A study published in the Journal of Clinical Lipidology [3] recommends monitoring liver function tests at baseline, 12 weeks, and then every six months for the first year of treatment with atorvastatin. After the first year, monitoring can be performed annually unless there are concerns about liver function.

In summary, it is recommended to perform liver function tests before starting Lipitor and then periodically thereafter. The frequency of monitoring may vary depending on the individual patient and their medical history. However, a general guideline is to perform tests after 12 weeks of treatment and then every six months to a year if there are no concerns about liver function. It is important to consult with a healthcare provider for personalized monitoring recommendations.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.health.harvard.edu/diseases-and-conditions/ask-the-doctor-statins-and-liver-tests
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5325661/