Yes, grapefruit juice can interact negatively with Lipitor (atorvastatin), a medication used to treat high cholesterol levels. This interaction can lead to an increased concentration of the drug in the bloodstream, which may enhance the risk and severity of side effects [1].

The primary component in grapefruit juice responsible for this interaction is furanocoumarin [1]. When consumed together, furanocoumarin can inhibit an enzyme called cytochrome P450 3A4 (CYP3A4) in the small intestine [1]. CYP3A4 is responsible for metabolizing several medications, including Lipitor [1]. As a result, when CYP3A4 is inhibited, the drug remains in the body for a more extended period, leading to higher concentrations of atorvastatin in the bloodstream [1].

Possible side effects of increased atorvastatin concentrations include muscle pain, liver damage, and kidney damage [1]. Patients should consult their healthcare provider before consuming grapefruit juice or any grapefruit products while taking Lipitor [1].

Sources:

1. [DrugPatentWatch.com](https://www.drugpatentwatch.com/drugs/lipitor/interactions)