Based on the information provided, I was unable to find a specific recommendation for how often lipitor levels should be checked. However, it is generally recommended that patients on statin therapy, such as Lipitor, have their liver function and cholesterol levels monitored regularly [1]. The specific frequency may depend on various factors, including the individual's response to treatment, the presence of any side effects, and the patient's overall health status.

It is important to note that Lipitor is a medication that is used to lower cholesterol levels in the blood, and it works by blocking the action of a certain enzyme in the body that is needed to make cholesterol. Regular monitoring of lipid levels is necessary to ensure that the medication is working effectively and that the patient's cholesterol levels are within the target range.

In addition, it is also important to monitor liver function as statins, including Lipitor, can cause an increase in liver enzymes. Therefore, it is recommended that patients on Lipitor have their liver function tested before starting the medication and then at regular intervals thereafter [2].

In summary, while there is no specific recommended frequency for lipitor level checks, it is important for patients on Lipitor to have their liver function and cholesterol levels monitored regularly. The specific frequency may depend on various factors and should be determined by a healthcare professional.

Sources:

* [1] American Heart Association. (2021). Statins. <https://www.heart.org/en/health-topics/cholesterol/statins-lower-cholesterol-what-you-need-to-know>
* [2] Lipitor (atorvastatin) tablets, for oral use. (2019). Highlights of prescribing information. Pfizer Labs. <https://www.accessdata.fda.gov/drugsatfda_docs/label/2019/020762s053lbl.pdf>
* [3] DrugPatentWatch. (n.d.). Lipitor. <https://www.drugpatentwatch.com/drugs/lipitor>