Vascepa and niacin are both medications that are commonly used to treat high cholesterol levels. However, it is important to note that both of these drugs can interact negatively with other medications.

According to DrugPatentWatch [1], Vascepa's active ingredient is eicosapentaenoic acid (EPA), which is a type of omega-3 fatty acid. It is typically used to lower triglyceride levels in the blood. Vascepa may interact with blood thinners, such as warfarin, and increase the risk of bleeding. It is important to inform your doctor if you are taking any blood thinners before starting Vascepa.

Niacin, on the other hand, is a B vitamin that is used to lower cholesterol levels. According to Drugs.com [2], niacin may interact with a wide range of medications, including blood thinners, diabetes medications, and antibiotics. Niacin can also interact with other cholesterol-lowering drugs, such as statins, and increase the risk of muscle damage.

In addition, both Vascepa and niacin can cause side effects when taken with other medications. For example, Vascepa may increase the risk of bleeding when taken with aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) [3]. Niacin may increase the risk of liver damage when taken with other medications that can affect liver function [2].

It is important to talk to your doctor or pharmacist before taking Vascepa or niacin with any other medications. They can help you understand the potential risks and benefits of combining these drugs with other medications, and can recommend alternative treatments if necessary.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/VASCEPA
[2] https://www.drugs.com/drug-interactions/niacin.html
[3] https://www.ncbi.nlm.nih.gov/books/NBK425699/