Lipitor is a brand name for the drug atorvastatin, which is a type of statin medication used to lower cholesterol levels in the blood [2]. Statins work by blocking an enzyme that produces cholesterol in the liver, which can reduce the risk of heart disease and stroke [2]. However, some people may experience side effects from taking statins, such as muscle pain, liver damage, and digestive problems [3].

There could be several reasons why someone may switch from Lipitor to a different medication. One reason could be that they experience intolerable side effects from taking Lipitor [3]. In this case, a doctor may recommend switching to a different statin medication or a non-statin medication to lower cholesterol levels [3]. Another reason could be that Lipitor is not effectively lowering the person's cholesterol levels, and a different medication or combination of medications may be needed [2].

It is important to note that any decision to switch medications should be made in consultation with a healthcare provider. They can evaluate the individual's specific health needs and medical history to determine the best course of treatment [2].

Sources:
[2] https://my.clevelandclinic.org/health/treatments/22282-statins
[3] https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/statin-side-effects/art-20046013