It is advisable to avoid grapefruit products while taking Lipitor (atorvastatin), a medication used to lower cholesterol levels, as grapefruit can interact with the drug and increase the risk of side effects [2][3]. Grapefruit contains compounds that can interfere with the enzymes responsible for breaking down Lipitor in the liver, leading to an increase in the concentration of the drug in the bloodstream [2]. This can cause an overdose of the medication, leading to adverse effects such as muscle pain, liver damage, and kidney failure [2][3]. Therefore, it is best to avoid grapefruit products, including grapefruit juice, fresh grapefruit, and grapefruit supplements, while taking Lipitor [2][3]. It is also important to consult with a healthcare provider before making any changes to medication or diet [2].

Sources:
[2] https://www.healthline.com/health/high-cholesterol/grapefruit-and-statins
[3] https://www.goodrx.com/classes/statins/why-cant-i-have-grapefruit-with-my-statin