Glucosamine is a popular dietary supplement used for joint pain relief, and it is often taken in combination with other medications. Lipitor (atorvastatin) is a prescription medication used to lower cholesterol levels in the blood. According to the sources provided, there is no direct interaction between glucosamine and Lipitor, but there are some precautions to be taken when taking these two medications together.

The first source, Drug Patent Watch [1], provides information about the composition and patent status of Lipitor. The second source, a study published in the National Center for Biotechnology Information [2], explains that glucosamine is metabolized in the liver, and it may affect the activity of certain enzymes that are involved in the metabolism of other drugs. However, the study did not find any significant interaction between glucosamine and atorvastatin.

The third source, NHS [3], recommends caution when taking glucosamine with Lipitor, as some people may experience an increase in liver enzymes, which could indicate liver damage. This is more likely to occur in people who already have liver problems or who take high doses of both medications. Therefore, it is advisable to consult a doctor before taking these two medications together.

In conclusion, there is no direct interaction between glucosamine and Lipitor, but caution should be exercised when taking them together, especially in people with liver problems or those taking high doses of both medications. It is always recommended to consult a healthcare provider before taking any new medication or supplement, especially if you are already taking other medications.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3456914/
[3] https://www.nhs.uk/medicines/atorvastatin/taking-atorvastatin-with-other-medicines-and-herbal-supplements/