Lipitor is a medication used to lower cholesterol levels and is a brand name for atorvastatin calcium. According to Drug Patent Watch , Lipitor's patent expired in 2011, which means that generic versions of the medication are available.
Regarding coverage for pre-existing conditions, Medicare Interactive  explains that Medigap policies are supplemental insurance policies that are designed to cover some of the out-of-pocket costs that Original Medicare does not cover. However, Medigap policies may not cover pre-existing conditions during the first six months of coverage.
A study published in the US National Library of Medicine National Institutes of Health  found that the Affordable Care Act (ACA) has made it illegal for health insurance companies to deny coverage or charge higher premiums based on pre-existing conditions. However, it is important to note that this law applies to private health insurance plans and not necessarily to Medicare or Medigap policies.
In conclusion, while Lipitor is available in generic form and may be covered by insurance, coverage for pre-existing conditions may vary depending on the type of insurance plan. Medigap policies may not cover pre-existing conditions during the first six months of coverage, and the ACA's protections against denying coverage or charging higher premiums for pre-existing conditions may not necessarily apply to Medicare or Medigap policies. It is best to check with your specific insurance provider for more information on coverage for pre-existing conditions.