Lipitor is a brand name for the drug atorvastatin, which is a medication used to lower cholesterol levels and reduce the risk of heart disease [1]. According to the sources provided, there are several known interactions with Lipitor that patients should be aware of.

One source, Drug Patent Watch [1], lists several drugs that may interact with Lipitor, including cyclosporine, gemfibrozil, and niacin. Cyclosporine may increase the levels of Lipitor in the blood, which could lead to an increased risk of side effects. Gemfibrozil may also increase the risk of side effects, and niacin may increase the risk of muscle problems.

Another source, Drugs.com [2], provides a more comprehensive list of drugs that may interact with Lipitor. Some of the drugs on this list include:

- Antibiotics like erythromycin and clarithromycin
- Antifungal medications like itraconazole and ketoconazole
- Antidepressants like fluoxetine and sertraline
- Blood thinners like warfarin
- Calcium channel blockers like amlodipine and diltiazem
- HIV medications like ritonavir and saquinavir

These drugs may interact with Lipitor in various ways, such as increasing the risk of side effects or reducing the effectiveness of Lipitor in lowering cholesterol levels.

Finally, GoodRx [3] provides a list of common drug interactions with atorvastatin (the generic name for Lipitor). This list includes many of the same drugs as the Drugs.com list, as well as some additional medications like certain birth control pills and immunosuppressants.

It is important for patients taking Lipitor to inform their healthcare provider of all medications they are taking, including prescription drugs, over-the-counter medications, and herbal supplements. This can help prevent potentially harmful interactions and ensure that Lipitor is being used safely and effectively.

Sources:
1. https://www.drugpatentwatch.com/p/tradename/LIPITOR
2. https://www.drugs.com/drug-interactions/atorvastatin,lipitor.html
3. https://www.goodrx.com/atorvastatin/interactions