Based on the available information, there are several issues that could potentially lead to a change in Lipitor (atorvastatin) dosage. Lipitor is a medication used to treat high blood cholesterol levels and prevent heart disease [1].

One reason for a dosage change may be the patient's response to the medication. If a patient is not achieving their target cholesterol levels, their healthcare provider may increase the dosage [1]. On the other hand, if a patient experiences side effects, their healthcare provider may decrease the dosage or recommend a different medication [2].

Common side effects of Lipitor include muscle pain, liver damage, and digestive problems [2]. In rare cases, Lipitor has been associated with memory loss and confusion [3]. If a patient experiences any of these side effects, they should contact their healthcare provider.

In addition, certain factors may increase a patient's risk of side effects and require a dosage adjustment. These factors include age, kidney or liver function, and the use of other medications [2]. For example, Lipitor should be used with caution in older adults and patients with liver disease [2].

It is important for patients to follow their healthcare provider's instructions regarding Lipitor dosage. Patients should not change their dosage or stop taking Lipitor without consulting their healthcare provider [2].

In summary, issues that may lead to a change in Lipitor dosage include the patient's response to the medication, side effects, and certain factors such as age, kidney or liver function, and the use of other medications.

Sources:
[1] <https://www.drugpatentwatch.com/p/tradename/LIPITOR>
[2] <https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/statin-side-effects/art-20046013>
[3] <https://www.medicalnewstoday.com/articles/drugs-lipitor-side-effects>