Lipitor is a medication used to lower cholesterol levels in the body. According to the sources provided, it is possible for allergies to develop over time while taking Lipitor.

The first source, Drug Patent Watch [1], provides information on the patent status of Lipitor but does not directly address the question at hand.

The second source, Medical News Today [2], lists several potential side effects of Lipitor, including allergic reactions. The article notes that while rare, allergic reactions can occur while taking Lipitor. Symptoms of an allergic reaction can include hives, difficulty breathing, and swelling of the face, lips, tongue, or throat. The article also notes that if someone experiences an allergic reaction while taking Lipitor, they should seek medical attention immediately.

The third source, Mayo Clinic [3], also lists allergic reactions as a potential side effect of Lipitor. The article notes that while rare, Lipitor can cause an allergic reaction that can be life-threatening. The article also notes that if someone experiences symptoms of an allergic reaction while taking Lipitor, they should seek emergency medical attention.

In conclusion, according to the sources provided, it is possible for allergies to develop over time while taking Lipitor. While rare, allergic reactions can occur and can be life-threatening. If someone experiences symptoms of an allergic reaction while taking Lipitor, they should seek medical attention immediately.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.medicalnewstoday.com/articles/drugs-lipitor-side-effects
[3] https://www.mayoclinic.org/drugs-supplements/atorvastatin-oral-route/side-effects/drg-20067003