Lipitor is a medication that is commonly prescribed to lower cholesterol levels in the blood [1]. According to the FDA, grapefruit juice can interfere with the effectiveness of some medications, including Lipitor [3]. However, there is no evidence to suggest that orange juice has a similar effect. In fact, a study published in the Journal of Food and Drug Analysis found that orange juice did not interfere with the absorption of atorvastatin, the active ingredient in Lipitor [2]. Therefore, it is unlikely that orange juice will reduce the effectiveness of Lipitor. However, patients should always consult with their healthcare provider before making any changes to their medication regimen.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3589309/
[3] https://www.fda.gov/consumers/consumer-updates/grapefruit-juice-and-some-drugs-dont-mix