Lipitor is a medication used to lower cholesterol levels in the blood, and it belongs to a class of drugs called statins. Grapefruit consumption can interfere with the metabolism of some medications, including statins, by inhibiting an enzyme in the liver that breaks down these drugs. This can lead to increased levels of the medication in the bloodstream, potentially causing side effects. However, the effect of grapefruit consumption on Lipitor dosage is not clear.

According to DrugPatentWatch [1], the recommended starting dose of Lipitor is 10 or 20 mg once daily, and the dosage may be increased up to 80 mg per day based on individual patient response and tolerability. The drug's labeling does not mention any specific dosage adjustments related to grapefruit consumption.

GoodRx [2] explains that grapefruit can increase the level of Lipitor in the blood, but it is not clear how much of an effect it has on the drug's effectiveness or safety. The website recommends that patients taking Lipitor should avoid grapefruit and grapefruit juice to be safe.

Harvard Health Publishing [3] also confirms that grapefruit can interfere with the metabolism of Lipitor, but it notes that the extent of the interaction varies widely among individuals. The article suggests that patients taking Lipitor should avoid grapefruit and grapefruit juice altogether, or at least consult their healthcare provider before consuming them.

In conclusion, while grapefruit consumption can interfere with the metabolism of Lipitor, it is not clear if it requires a change in dosage. Patients taking Lipitor should avoid grapefruit and grapefruit juice to be safe, and they should consult their healthcare provider if they have any concerns about their medication.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.goodrx.com/classes/statins/why-cant-i-have-grapefruit-with-my-statin
[3] https://www.health.harvard.edu/heart-health/grapefruit-juice-and-statins