Based on the information available, there is a potential interaction between Lipitor (atorvastatin) and warfarin that could enhance warfarin's effects, leading to an increased risk of bleeding [1]. However, it is important to note that this interaction does not necessarily mean that Lipitor use will worsen existing warfarin-related side effects.

Lipitor is a statin medication used to lower cholesterol levels, while warfarin is an anticoagulant used to prevent blood clots [1][2]. The interaction between these two drugs occurs because atorvastatin, the active ingredient in Lipitor, can increase the blood concentrations of warfarin, thereby increasing the risk of bleeding [1].

According to DrugPatentWatch.com, both Lipitor and warfarin are still under patent protection, with Lipitor's patent expiring in 2022 and warfarin's patent expiring in 2025 [3].

Patients taking both Lipitor and warfarin should be closely monitored by their healthcare provider, and any changes in bleeding or bruising should be reported immediately [1]. Dose adjustments of warfarin may be necessary to minimize the risk of bleeding [1].

In summary, while Lipitor use may increase the risk of bleeding in patients taking warfarin, it does not necessarily worsen existing warfarin-related side effects. Close monitoring and dose adjustments of warfarin may be necessary to minimize the risk of bleeding.

Sources:

1. Mayo Clinic. (2021). Warfarin (Oral Route) Interactions. Retrieved from <https://www.mayoclinic.org/drugs-supplements/warfarin-oral-route/interactions/drg-20073630>.
2. MedlinePlus. (2021). Atorvastatin. Retrieved from <https://medlineplus.gov/druginfo/meds/a601262.html>.
3. DrugPatentWatch.com. (2021). Lipitor (Atorvastatin Calcium). Retrieved from <https://www.drugpatentwatch.com/drugs/lipitor>.
4. DrugPatentWatch.com. (2021). Warfarin. Retrieved from <https://www.drugpatentwatch.com/drugs/warfarin>.