According to the sources provided, Lipitor (atorvastatin) does not appear to have a significant effect on antidepressant dosage.

The first source [1] provides information on Lipitor's patent expiration and does not mention any interactions with antidepressants.

The second source [2] is a study that aimed to investigate the effects of atorvastatin on depression and anxiety in patients with coronary artery disease. While the study found that atorvastatin did not significantly improve depression or anxiety symptoms, it did not report any interactions between atorvastatin and antidepressants.

The third source [3] is a review article that discusses the potential interactions between statins (including atorvastatin) and antidepressants. The article notes that some studies have suggested that statins may enhance the effects of certain antidepressants, while others have suggested that statins may reduce the effectiveness of certain antidepressants. However, the article also notes that the evidence for these interactions is limited and inconsistent, and that more research is needed to fully understand the potential interactions between statins and antidepressants.

In summary, while there is some limited evidence suggesting that statins (including atorvastatin) may interact with certain antidepressants, the available evidence does not suggest that Lipitor has a significant effect on antidepressant dosage. As with any medication, patients should consult with their healthcare provider before starting or stopping any medications, including Lipitor and antidepressants.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://pubmed.ncbi.nlm.nih.gov/25446923/
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9827898/