When combining Lipitor (atorvastatin), a cholesterol-lowering medication, with fish oil, certain side effects may occur. However, it is essential to understand that individual experiences can vary, and not everyone will encounter these side effects [1].

Potential side effects of mixing Lipitor and fish oil include:

1. Muscle pain or weakness: Both Lipitor and fish oil can independently cause muscle-related side effects. When used together, the risk may be slightly increased, leading to conditions such as myalgia or myopathy [1][2].
2. Liver enzyme abnormalities: Atorvastatin can increase liver enzymes, and fish oil may also affect liver function. Therefore, combining the two might increase the likelihood of liver enzyme abnormalities [1][3].
3. Gastrointestinal issues: Fish oil can cause gastrointestinal side effects like nausea, diarrhea, and bloating. When taken with Lipitor, these symptoms might be more pronounced [1][3].
4. Increased bleeding risk: Both Lipitor and fish oil can affect blood clotting, increasing the risk of bleeding, especially when taken together [1][3].

It is crucial to consult a healthcare professional before starting or changing any medication regimen, including combining Lipitor and fish oil. Physicians can provide personalized advice based on an individual's health history and current medications [1].

Sources:

1. [DrugPatentWatch.com](https://www.drugpatentwatch.com/drugs/atorvastatin). Atorvastatin (Lipitor) - DrugPatentWatch.
2. National Library of Medicine. (2019). Atorvastatin. <https://medlineplus.gov/druginfo/meds/a601265.html>.
3. National Library of Medicine. (2021). Fish Oil. <https://medlineplus.gov/druginfo/natural/993.html>.