Lipitor is a brand name for atorvastatin, which is a medication used to lower cholesterol levels in the blood. Warfarin is a medication used to prevent blood clots. According to the sources provided, there is a potential for bleeding when taking both Lipitor and warfarin together.

The Drug Patent Watch [1] states that there are no known drug interactions between Lipitor and warfarin. However, the National Center for Biotechnology Information [2] reports that some studies have shown that taking atorvastatin with warfarin can increase the risk of bleeding. This is because atorvastatin can increase the concentration of warfarin in the blood, leading to an increased risk of bleeding.

Furthermore, NBC News [3] reported that marijuana use can also increase the risk of bleeding when taking warfarin. This is because marijuana can interact with warfarin and increase its effects, leading to an increased risk of bleeding.

It is important to note that every person's body reacts differently to medications, and the risk of bleeding may vary from person to person. Therefore, it is essential to consult with a healthcare provider before taking any new medications or supplements, especially when taking warfarin.

In conclusion, while there are no known drug interactions between Lipitor and warfarin, some studies have shown that taking atorvastatin with warfarin can increase the risk of bleeding. Additionally, marijuana use can also increase the risk of bleeding when taking warfarin. It is crucial to consult with a healthcare provider before taking any new medications or supplements, especially when taking warfarin.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2813204/
[3] https://www.nbcnews.com/health/heart-health/marijuana-risky-people-taking-common-heart-medications-n1118181