The sources provided do not provide information on whether the dosage of Lipitor should be adjusted with antihistamines. However, they do provide information on drug interactions that should be taken into consideration when taking Lipitor with other medications.

According to Drug Patent Watch [1], Lipitor's active ingredient is atorvastatin calcium, which is used to lower cholesterol levels in the blood. The website does not provide any information on drug interactions with antihistamines.

The COVID-19 Treatment Guidelines [2] provide information on drug interactions between Lipitor and Ritonavir-boosted nirmatrelvir, which is a medication used to treat COVID-19. The guidelines state that Ritonavir-boosted nirmatrelvir can increase the concentration of atorvastatin in the blood, which can increase the risk of side effects. Therefore, the dosage of Lipitor should be reduced to 20 mg per day when taken with Ritonavir-boosted nirmatrelvir.

The Trikafta HCP [3] website provides information on drug interactions between Lipitor and Trikafta, which is a medication used to treat cystic fibrosis. The website states that Lipitor can increase the concentration of Trikafta in the blood, which can increase the risk of side effects. Therefore, the dosage of Trikafta should be reduced when taken with Lipitor.

In conclusion, the sources provided do not provide information on whether the dosage of Lipitor should be adjusted with antihistamines. However, it is important to consider drug interactions when taking Lipitor with other medications, such as Ritonavir-boosted nirmatrelvir and Trikafta. Patients should consult with their healthcare provider before taking Lipitor with any other medications, including antihistamines.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.covid19treatmentguidelines.nih.gov/therapies/antivirals-including-antibody-products/ritonavir-boosted-nirmatrelvir--paxlovid-/paxlovid-drug-drug-interactions/
[3] https://www.trikaftahcp.com/drug-interactions